What do you think is happening to this cell? Homework: 10 Key Ideas Warm-UP: What do you think is happening to this cell? Homework: 10 Key Ideas Section 12.1 AP Test Money DUE: NEXT FRIDAY! 3/6 Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too!
Topics Essential Knowledge Concept 13.1: What are the advantages to sexual/asexual reproduction? What is the relationship between a gene, a chromosome, and DNA? Concept 13.2: What happens to a cell during meiosis? Compare mitosis and meiosis? Why bother doing meiosis? Concept 13.4: When is genetic diversity increased during meiosis? How? What is the advantage to this? Concept 14.1: How can we predict the offspring of parents using punnett squares (monohybrid, dihybrid)? Explain why some traits are dominant to others. Explain how variation is increased due to independent assortment. Concept 14.2: Use probability laws to solve punnett squares predicting the outcomes of crosses where many traits are involved. Concept 14.3: Inheritance patterns are more complex that simple dominance/recessive: incomplete dominance, blood types, codominance Concept 14.4: Use a pedigree analysis of a family to make predictions about future offspring. Concept 15.1: What did Morgan tell us that Mendel couldn’t? How do chromosomes explain Mendel’s 3:1 ratio? Concept 15.2: Explain how sex is determined. Why do some diseases show in boys more often than girls? Concept 15.3: How do linked genes complicate Mendel’s findings? 3.a.2: In eukaryotes, heritable info. is passed to the next generation via mitosis and meiosis 3.a.3: The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring 3.a.4: The inheritance pattern of many traits cannot be explained by simple Mendelian genetics 3.c.2: Biological systems have multiple processes that increase genetic variation
Unit 7: Inheritance Big Idea: In eukaryotic organisms, heritable information is passed to the next generation via mitosis and meiosis, which has multiple processes that increases genetic variation. The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. The chromosomal basis of inheritance explains pattern of transmission of genes from parent to offspring.
Drawing Description 0:25 – In eukaryotic organisms, heritable information is passed to the next generation via mitosis and meiosis Time (seconds) Drawing Description 0:25 – 0:30 – 0:35– 0:40 – 0:45 – 0:50-
Chromosome Model Materials: pipe cleaners beads cotton balls tape string Procedure add 3-5 beads to a pipe cleaner to model genes twist a 2nd pipe cleaner to the 1st to model the double helix tie string to the beads to model mRNA wrap the whole model around a cotton ball to represent how DNA supercoils around histones in order to get smaller replicate the 1st to model a sister chromatid tape it to the 1st at about the middle to model the centromere
Chromosome Model Parts chromosome: tightly coiled DNA double helix: DNA is 2 strands of nucleotides twisted together. gene: small sections of DNA that encode traits histone: proteins that DNA supercoils around; makes the DNA smaller so that it can fit in our cells sister chromatid: a duplicated copy of the original DNA, still connected to the 1st centromere: the place where the 2 sister chromatids are connected (DNA Replication not quite finished) mRNA: copies of DNA that read genes Procedure add 3-5 beads to a pipe cleaner to model genes twist a 2nd pipe cleaner to the 1st to model the double helix tie string to the beads to model mRNA transcribing DNA wrap the whole model around a cotton ball to represent how DNA supercoils around histones in order to get smaller replicate the 1st to model a sister chromatid tape it to the 1st at about the middle to model the centromere
Chromosome Model Materials: pipe cleaners beads cotton balls tape Parts chromosome: tightly coiled DNA double helix: DNA is 2 strands of nucleotides twisted together. gene: small sections of DNA that encode traits histone: proteins that DNA supercoils around; makes the DNA smaller so that it can fit in our cells sister chromatid: a duplicated copy of the original DNA, still connected to the 1st centromere: the place where the 2 sister chromatids are connected mRNA: copies of DNA that read genes
Chromosome Model Materials: pipe cleaners beads cotton balls tape Parts chromosome: tightly coiled DNA double helix: DNA is 2 strands of nucleotides twisted together. gene: small sections of DNA that encode traits histone: proteins that DNA supercoils around; makes the DNA smaller so that it can fit in our cells sister chromatid: a duplicated copy of the original DNA, still connected to the 1st centromere: the place where the 2 sister chromatids are connected mRNA: copies of DNA that read genes
Chromosome Model Materials: pipe cleaners beads cotton balls tape Parts chromosome: tightly coiled DNA double helix: DNA is 2 strands of nucleotides twisted together. gene: small sections of DNA that encode traits histone: proteins that DNA supercoils around; makes the DNA smaller so that it can fit in our cells sister chromatid: a duplicated copy of the original DNA, still connected to the 1st centromere: the place where the 2 sister chromatids are connected mRNA: copies of DNA that read genes
Warm-UP: Can you “unwind” your model like in the picture to show the parts? Sketch and label your model (or the picture of the model). Labels: histone, mRNA, DNA, sister chromatid, centromere AP Test Money DUE: 3/6 Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too! Homework for Tonight: Mitosis Worksheet UNIT 7/8 TEST: March 19th Inheritance and Regulation Due Now: Stamp Sheet
In what ways are cells different than each other? the same? Warm-UP: Is blowing up a balloon a good model for how cells or organisms grow? Explain In what ways are cells different than each other? the same? AP Test Money DUE: 3/6 Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too! Homework for Tonight: 12.2 UNIT 7/8 TEST: March 19th Inheritance and Regulation
In what ways are cells different than each other? the same? Warm-UP: Is blowing up a balloon a good model for how cells or organisms grow? Explain In what ways are cells different than each other? the same? AP Test Money DUE: 3/6 Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too! Homework for Tonight:
In what ways are cells different than each other? the same? Warm-UP: Is blowing up a balloon a good model for how cells or organisms grow? Explain In what ways are cells different than each other? the same? AP Test Money DUE: 3/6 Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too! Homework for Tonight:
In what ways are cells different than each other? the same? Warm-UP: Is blowing up a balloon a good model for how cells or organisms grow? Explain In what ways are cells different than each other? the same? AP Test Money DUE: 3/6 Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too! Homework for Tonight:
In eukaryotic organisms, heritable information is passed to the next generation via mitosis and meiosis Cell Division: 2 Types: Mitosis and Meiosis Mitosis Purpose: growth repair asexual reproduction (actually binary fission in prokaryotes) occurs after DNA replication is followed by cytokinesis 2 genetically identical daughter cells (clones) Steps: Replication Alignment Separation
Mitosis Modeling Draw a big cell with a nucleus inside. Add homologous pairs of chromosomes: 1 big yellow, 1 big white 1 medium yellow, 1 medium white 1 small yellow, 1 small white Clone each chromosome (DNA Replication) (making sister chromatids) Nucleus breaks down (erase it). Clones separate: one to each side of cell Cytokinesis: cell membrane "grows" between the 2 halves Nucleus "grows" around chromosomes When you’re confident on the process, show Mr. Jones.
Mitosis Modeling When you’re confident on the process, show Mr. Jones. In your notebook: Table 12.7: Stages of Mitosis: p.232 At each stage, describe what is happening in 1-2 sentences. DO NOT COPY DRAW with LABELS: cell membrane nucleus chromosome DNA replication cytokinesis sister chromatid
Mitosis Modeling Analysis What is the outcome of mitosis? What steps of mitosis ensure a perfect outcome? If the first cell has 46 chromosomes (before cloning), how many does each daughter cell have? Why do cells go through mitosis?
Words to Know: Nucleus DNA Histones Chromatin Chromosome Chromatid Centromere Interphase: “S” phase Mitosis: Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Warm-UP: Advantages of Sex? Disadvantages of Sex? UNIT 7/8 TEST: AP Test Money DUE: 3/6 Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too! Homework DUE Thurs: Meiosis Wksht UNIT 7/8 TEST: March 19th Inheritance and Regulation
Asexual Reproduction 0.5 mm Bacteria Parent Plants Bud Advantages: Fig. 13-2 Asexual Reproduction 0.5 mm Bacteria Advantages: Can be done in isolation. If you are perfect, why change? Best when an organism is “perfectly” suited for its environment Less “machinery” needed: no waste on flowers, “new” types of cells, or other secondary sexual characteristics Disadvantages: Less variety: Poor option in a changing environment Parent Plants Figure 13.2 Asexual reproduction in two multicellular organisms Bud
Asexual Reproduction 0.5 mm Parent Bud Advantages: Fig. 13-2 Asexual Reproduction 0.5 mm Advantages: Can be done in isolation. If you are perfect, why change? Best when an organism is “perfectly” suited for its environment Less “machinery” needed: no waste on flowers, “new” types of cells, or other secondary sexual characteristics Disadvantages: Less variety: Poor option in a changing environment Parent Figure 13.2 Asexual reproduction in two multicellular organisms Bud
Asexual Reproduction 0.5 mm Aspen Parent Bud Advantages: Fig. 13-2 Asexual Reproduction 0.5 mm Advantages: Can be done in isolation. If you are perfect, why change? Best when an organism is “perfectly” suited for its environment Less “machinery” needed: no waste on flowers, “new” types of cells, or other secondary sexual characteristics Disadvantages: Less variety: Poor option in a changing environment Aspen Parent Figure 13.2 Asexual reproduction in two multicellular organisms Bud
Sexual Reproduction Advantages: Fig. 13-1 Sexual Reproduction Advantages: Increased variety: Best when environment is changing Increased Variety is DUE TO: random fertilization meiosis: independent assortment crossing-over Disadvantages: Resource investment: specialized cells: gametes secondary sexual characteristics: mate attraction Requires a partner (except when plants self-fertilize) Figure 13.1 What accounts for family resemblance?
In eukaryotic organisms, heritable information is passed to the next generation via mitosis and meiosis Cell Division: 2 Types: Meiosis: sex cells (gametes) (sperm/eggs) Purpose: ensures that each gamete receives one complete haploid (1n) set of chromosomes Ensures chromosome number stays the same: each offspring receives ½ (1n) of the full set for the species (2n) Steps: DNA Replication homologous pairs form a tetrad (independent assortment) (genetic variation increases) cross over between homologous chromosomes may occur (genetic variation increases) Meiosis I: homologous pairs separate Meiosis II: sister chromatids separate
In eukaryotic organisms, heritable information is passed to the next generation via mitosis and meiosis Cell Division: 2 Types: Meiosis: sex cells (gametes) (sperm/eggs) Purpose: ensures that each gamete receives one complete haploid (1n) set of chromosomes Ensures chromosome number stays the same: each offspring receives ½ (1n) of the full set for the species (2n) Steps: DNA Replication homologous pairs form a tetrad (independent assortment) (genetic variation increases) cross over between homologous chromosomes may occur (genetic variation increases) Meiosis I: homologous pairs separate Meiosis II: sister chromatids separate
In eukaryotic organisms, heritable information is passed to the next generation via mitosis and meiosis Cell Division: 2 Types: Meiosis: sex cells (gametes) (sperm/eggs) Purpose: ensures that each gamete receives one complete haploid (1n) set of chromosomes Ensures chromosome number stays the same: each offspring receives ½ (1n) of the full set for the species (2n) Steps: DNA Replication homologous pairs form a tetrad (independent assortment) (genetic variation increases) cross over between homologous chromosomes may occur (genetic variation increases) Meiosis I: homologous pairs separate Meiosis II: sister chromatids separate
Meiosis Modeling When you’re confident on the process, show Mr. Jones. Build your diploid cell (an homologous pair for each chromosome) Draw a big cell with a nucleus inside. Add homologous pairs of chromosomes: 1 big white, 1 big yellow 1 medium white, 1 medium yellow 1 small white, 1 small yellow Clone each chromosome (DNA Replication) (making sister chromatids) Nucleus breaks down (erase it). Homologous pairs form a tetrad: crossing over may occur. (note: do not model crossing over for now) Homologous pairs separate one to each side of cell: all paternal (or all maternal) do NOT have to go together (independent assortment) Cytokinesis: cell membrane "grows" between the 2 halves Clones (sister chromatids) separate (centromere “breaks” as DNA polymerization completes): one to each side of cell Nucleus "grows" around chromosomes. 4 cells made (gametes, which have half the number of chromosomes (haploids) When you’re confident on the process, show Mr. Jones.
Meiosis Modeling When you’re confident on the process, show Mr. Jones. In your notebook: Table 13.8: Stages of Meiosis: p.255 At each stage, describe what is happening in 1-2 sentences. DO NOT COPY DRAW with LABELS: cell membrane nucleus chromosome DNA replication cytokinesis sister chromatid crossing over recombinant chromosome independent assortment Meiosis I Meiosis II
Meiosis Modeling Analysis What is the outcome of meiosis? What steps of meiosis cause variation? If the first cell has 46 chromosomes (before cloning), how many does each daughter cell have? How many unique gametes did you form? How many could have formed? Why do cells go through meiosis?
Warm-UP: 1. Why do meiosis? 2. How does meiosis increase variation in organisms? AP Test Money DUE: 3/6 Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too! Homework DUE Tomorrow: Meiosis Wksht UNIT 7/8 TEST: March 19th Inheritance and Regulation
Meiosis has multiple processes that increases genetic variation Genetic Variation is due to: Mutations (last unit) Meiosis: Independent assortment of chromosomes: paternal (red) chromosomes may/may not move together during Meiosis I causes an organism with n homologous pairs to be able to produce 2n varieties of gametes instead of only 2 ex: humans: 223=8,388,608 Crossing over: swapping of sections of homologous pairs during Meiosis I; produces recombinant chromosomes causes “linked” genes to become “unlinked”: 2 alleles on the same chromosome may/may not move together during Meiosis I recombinant chromosomes have unique combinations of alleles Random fertilization: the particular combination of egg and sperm that results in the offspring is not predictable ex: humans: dad’s varieites of sperm (8,388,608) and mom’s varieites of eggs (8,388,608) can produce varieties 70,368,744,177,664 offpring
Meiosis has multiple processes that increase genetic variation Genetic Variation is due to: Mutations (last unit) Meiosis: Independent assortment of chromosomes: paternal (red) chromosomes may/may not move together during Meiosis I causes an organism with n homologous pairs to be able to produce 2n varieties of gametes instead of only 2 ex: humans: 223=8,388,608 Crossing over: swapping of sections of homologous pairs during Meiosis I; produces recombinant chromosomes causes “linked” genes to become “unlinked”: 2 alleles on the same chromosome may/may not move together during Meiosis I recombinant chromosomes have unique combinations of alleles Random fertilization: the particular combination of egg and sperm that results in the offspring is not predictable ex: humans: dad’s varieites of sperm (8,388,608) and mom’s varieites of eggs (8,388,608) can produce varieties 70,368,744,177,664 offpring Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings
Meiosis has multiple processes that increase genetic variation Genetic Variation is due to: Mutations (last unit) Meiosis: Independent assortment of chromosomes: paternal (red) chromosomes may/may not move together during Meiosis I causes an organism with n homologous pairs to be able to produce 2n varieties of gametes instead of only 2 ex: humans: 223=8,388,608 Crossing over: swapping of sections of homologous pairs during Meiosis I; produces recombinant chromosomes causes “linked” genes to become “unlinked”: 2 alleles on the same chromosome may/may not move together during Meiosis I recombinant chromosomes have unique combinations of alleles Random fertilization: the particular combination of egg and sperm that results in the offspring is not predictable ex: humans: dad’s varieites of sperm (8,388,608) and mom’s varieites of eggs (8,388,608) can produce varieties 70,368,744,177,664 offpring Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings
Meiosis has multiple processes that increases genetic variation Genetic Variation is due to: Mutations (last unit) Meiosis: Independent assortment of chromosomes: paternal (red) chromosomes may/may not move together during Meiosis I causes an organism with n homologous pairs to be able to produce 2n varieties of gametes instead of only 2 ex: humans: 223=8,388,608 Crossing over: swapping of sections of homologous pairs during Meiosis I; produces recombinant chromosomes causes “linked” genes to become “unlinked”: 2 alleles on the same chromosome may/may not move together during Meiosis I recombinant chromosomes have unique combinations of alleles Random fertilization: the particular combination of egg and sperm that results in the offspring is not predictable ex: humans: dad’s varieites of sperm (8,388,608) and mom’s varieites of eggs (8,388,608) can produce varieties 70,368,744,177,664 offpring
Warm-UP: Watch the video. What is happening. Why does this happen Warm-UP: Watch the video. What is happening? Why does this happen? How does this increase variation? AP Test Money DUE: TOMORROW 3/6 Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too! Homework DUE Tomorrow: ???? UNIT 7/8 TEST: March 19th Inheritance and Regulation
Replicated chromosome Fig. 13-9a MITOSIS MEIOSIS MEIOSIS I Parent cell Chiasma Chromosome replication Chromosome replication Prophase Prophase I Homologous chromosome pair 2n = 6 Replicated chromosome Metaphase Metaphase I Anaphase Telophase Anaphase I Figure 13.9 A comparison of mitosis and meiosis in diploid cells Telophase I Haploid n = 3 Daughter cells of meiosis I 2n 2n MEIOSIS II Daughter cells of mitosis n n n n Daughter cells of meiosis II
Types of Changes to Cells: Think About : what, where, when, how, how much variation created Compare: Contrast: Independent Assortment Crossing-over Sexual Fertilization Mutation
Warm-UP: Now we need to keep track of the genes on the chromosomes that are inherited. Notice the letters on the chromosomes. They represent different alleles for Huntington's. Barbie has Huntington's. What is the chance her child will get Huntington's? H=dominant (remember, Huntington’s is dominant) h=recessive (no Huntington’s) Homework DUE Tomorrow: 14.1: 5 Key Ideas AND Concept Check #1-3 Homework DUE Monday: Test Corrections for 10% Make-UP AP Test Money DUE: 3/6: TOMORROW Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too!
Warm-UP: Talk about your Concept Check with your table team Warm-UP: Talk about your Concept Check with your table team. Do you have agreement? Do you have questions? Homework DUE Monday: Test Corrections for 10% Make-UP Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? DUE next Thursday: Monohybrid Crosses AP Test Money DUE: 3/6: TODAY Remember, the 2nd semester Final Exam will be an AP test (the week before the official AP test); you might as well take the official test too!
Inheritance and Regulation Warm-UP: Now we need to keep track of TWO UNLINKED genes on the chromosomes that are inherited. Notice the letters on the chromosomes. They represent different alleles for Huntington's and red hair color. Barbie has Huntington's and is a blond (but a carrier). Ken does not have Huntington’s and is also a carrier for red hair. What is the chance their child will get Huntington's and red hair? Homework DUE Tomorrow: 14.2: 5 Key Ideas AND Concept Check #1-3 DUE Now: Test Corrections for 10% Make-UP UNIT 7/8 TEST: March 19th Inheritance and Regulation H= Huntington’s h=no Huntington’s R= no red hair r= red hair
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. P: Crossed purebreds F1: all one phenotype F2: 3:1 ratio Conclusion: “Alleles” segregate (in meiosis) independently Some alleles (dominant) hide the expression of others (recessive) Recessive alleles can appear again IF the dominant are no longer present Terms: allele: variety of a gene homozygous: both alleles are the same (purebred) heterozygous: alleles are different (carriers) (hybrids) Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. P: Crossed purebreds F1: all one phenotype F2: 3:1 ratio Conclusion: “Alleles” segregate (in meiosis) independently Some alleles (dominant) hide the expression of others (recessive) Recessive alleles can appear again IF the dominant are no longer present Terms: allele: variety of a gene homozygous: both alleles are the same (purebred) heterozygous: alleles are different (carriers) (hybrids) Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. P: Crossed purebreds F1: all one phenotype F2: 3:1 ratio Conclusion: “Alleles” segregate (in meiosis) independently Some alleles (dominant) hide the expression of others (recessive) Recessive alleles can appear again IF the dominant are no longer present Terms: allele: variety of a gene homozygous: both alleles are the same (purebred) heterozygous: alleles are different (carriers) (hybrids) Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Inheritance Patterns: Simple Dominance/Recessive: Mendel monohybrid cross: one trait di or tri hybrid cross: two or three traits, assuming independent assortment laws of probability vs punnett squares incomplete dominance: phenotype of hybrids is between the phenotypes of the purebreds codominance: two dominant alleles affect the phenotype in separate, distinguishable ways polygenic inheritance: an additive effect of two or more genes on a single phenotype x-linked genes: genes on the x chromosome are expressed by boys more often than girls b.c. boys only have one x chromosome (they cannot “mask” recessive alleles) linked genes: when 2 alleles are on the same chromosome, they show up together more often Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Inheritance Patterns: Simple Dominance/Recessive: Mendel monohybrid cross: one trait di or tri hybrid cross: two or three traits, assuming independent assortment laws of probability vs punnett squares incomplete dominance: phenotype of hybrids is between the phenotypes of the purebreds codominance: two dominant alleles affect the phenotype in separate, distinguishable ways polygenic inheritance: an additive effect of two or more genes on a single phenotype x-linked genes: genes on the x chromosome are expressed by boys more often than girls b.c. boys only have one x chromosome (they cannot “mask” recessive alleles) linked genes: when 2 alleles are on the same chromosome, they show up together more often Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Inheritance Patterns: Simple Dominance/Recessive: Mendel monohybrid cross: one trait di or tri hybrid cross: two or three traits, assuming independent assortment laws of probability vs punnett squares incomplete dominance: phenotype of hybrids is between the phenotypes of the purebreds codominance: two dominant alleles affect the phenotype in separate, distinguishable ways polygenic inheritance: an additive effect of two or more genes on a single phenotype x-linked genes: genes on the x chromosome are expressed by boys more often than girls b.c. boys only have one x chromosome (they cannot “mask” recessive alleles) linked genes: when 2 alleles are on the same chromosome, they show up together more often Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Inheritance Patterns: Simple Dominance/Recessive: Mendel monohybrid cross: one trait di or tri hybrid cross: two or three traits, assuming independent assortment laws of probability vs punnett squares incomplete dominance: phenotype of hybrids is between the phenotypes of the purebreds codominance: two dominant alleles affect the phenotype in separate, distinguishable ways polygenic inheritance: an additive effect of two or more genes on a single phenotype x-linked genes: genes on the x chromosome are expressed by boys more often than girls b.c. boys only have one x chromosome (they cannot “mask” recessive alleles) linked genes: when 2 alleles are on the same chromosome, they show up together more often Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Inheritance Patterns: Simple Dominance/Recessive: Mendel monohybrid cross: one trait di or tri hybrid cross: two or three traits, assuming independent assortment laws of probability vs punnett squares incomplete dominance: phenotype of hybrids is between the phenotypes of the purebreds codominance: two dominant alleles affect the phenotype in separate, distinguishable ways polygenic inheritance: an additive effect of two or more genes on a single phenotype x-linked genes: genes on the x chromosome are expressed by boys more often than girls b.c. boys only have one x chromosome (they cannot “mask” recessive alleles) linked genes: when 2 alleles are on the same chromosome, they show up together more often Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Inheritance Patterns: Simple Dominance/Recessive: Mendel monohybrid cross: one trait di or tri hybrid cross: two or three traits, assuming independent assortment laws of probability vs punnett squares incomplete dominance: phenotype of hybrids is between the phenotypes of the purebreds codominance: two dominant alleles affect the phenotype in separate, distinguishable ways polygenic inheritance: an additive effect of two or more genes on a single phenotype x-linked genes: genes on the x chromosome are expressed by boys more often than girls b.c. boys only have one x chromosome (they cannot “mask” recessive alleles) linked genes: when 2 alleles are on the same chromosome, they show up together more often Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Inheritance Patterns: Simple Dominance/Recessive: Mendel monohybrid cross: one trait di or tri hybrid cross: two or three traits, assuming independent assortment laws of probability vs punnett squares incomplete dominance: phenotype of hybrids is between the phenotypes of the purebreds codominance: two dominant alleles affect the phenotype in separate, distinguishable ways polygenic inheritance: an additive effect of two or more genes on a single phenotype x-linked genes: genes on the x chromosome are expressed by boys more often than girls b.c. boys only have one x chromosome (they cannot “mask” recessive alleles) linked genes: when 2 alleles are on the same chromosome, they show up together more often Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
Inheritance and Regulation Warm-UP: Talk about your Concept Check with your table team. Do you have agreement? Do you have questions? Homework DUE Tomorrow: 14.3: 5 Key Ideas AND Concept Check #1-3 Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? DUE Now: 14.2 DUE Thursday: Monohybrid Crosses to turnitin.com DUE Friday: Dihybrid Crosses to turnitin.com UNIT 7/8 TEST: March 19th Inheritance and Regulation
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Laws of Probability: skip Punnett squares instead, multiply likelyhoods Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Laws of Probability: skip Punnett squares instead, multiply likelyhoods ex: Chance of baby with RrYy? Chance of baby with Rr? 0.5 Chance of baby with Yy? 0.5 Chance of baby with RrYy? 0.25 Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Laws of Probability: skip Punnett squares instead, multiply likelyhoods ex: Chance of baby with both dominant phenotypes? Chance of baby with at least one R? 0.75 Chance of baby with at least one Y? 0.75 Chance of baby with RrYy? 0.5625 (9/16) Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The inheritance pattern of many traits cannot be explained by simple Mendelian genetics. Laws of Probability: skip Punnett squares instead, multiply likelyhoods ex: Chance of baby with both dominant phenotypes? Chance of baby with at least one R? 1.0 Chance of baby with at least one Y? 1.0 Chance of baby with both dominant phenotypes? 1.0 Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
Inheritance and Regulation Warm-UP: Talk about your Concept Check with your table team. Do you have agreement? Do you have questions? Homework DUE Tomorrow: Linked vs Unlinked Genes AND Monohybrid Crosses to tunritin.com DUE Friday: Dihybrid Crosses to turnitin.com Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? DUE Now: 14.3 UNIT 7/8 TEST: March 19th Inheritance and Regulation
Predict the phenotypic ratio of the F1 individuals. Warm-UP: A series of crosses is performed with fruit flies (Drosophila melanogaster) to examine inheritance of the genes vestigial (vg) and cinnabar (cn). The recessive vg allele causes small, malformed wings called vestigial wings. The recessive cn allele causes bright-red eyes called cinnabar eyes. In the first cross, a purebred female with wild-type wings and red eyes is mated with a purebred male with vestigial wings and cinnabar eyes. Predict the phenotypic ratio of the F1 individuals. In the second cross, female F1 flies are mated with males with vestigial wings and cinnabar eyes. Predict the phenotypic ratio of the F2 individuals. Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? Homework DUE Tomorrow: 15.3 5 Key Ideas and Concept Check #1-3 DUE Thursday: Monohybrid Crosses to turnitin.com DUE Friday: Dihybrid Crosses to turnitin.com DUE Now: 14.3 UNIT 7/8 TEST: March 19th Inheritance and Regulation
The two genes are located on two different chromosomes. Warm-UP: A series of crosses is performed with fruit flies (Drosophila melanogaster) to examine inheritance of the genes vestigial (vg) and cinnabar (cn). The recessive vg allele causes small, malformed wings called vestigial wings. The recessive cn allele causes bright-red eyes called cinnabar eyes. In the first cross, a purebred female with wild-type wings and red eyes is mated with a purebred male with vestigial wings and cinnabar eyes. Predict the phenotypic ratio of the F1 individuals. In the second cross, female F1 flies are mated with males with vestigial wings and cinnabar eyes. Predict the phenotypic ratio of the F2 individuals. The results of the cross from #2 show the following outcome. Individuals of each phenotype are shown in the table. Which of the following is the most likely explanation of the results? The two genes are located on two different chromosomes. The two genes are sex-linked. The two genes are located on mitochondrial DNA. The two genes are linked on an autosome. Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Morgan: experiments with fruit flies Interested in how linkage (when characters are on the same chromosome) affects inheritance of two characters crossed flies that differed in traits of body color and wing size Conclusions: body color and wing size are usually inherited together in specific combinations (parental phenotypes) these genes sometimes assort independently they must linked: on the same chromosome but the linkage is incomplete: cross-over sometimes creates recombinant chromosomes Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Morgan: experiments with fruit flies Interested in how linkage (when characters are on the same chromosome) affects inheritance of two characters crossed flies that differed in traits of body color and wing size Conclusions: body color and wing size are usually inherited together in specific combinations (parental phenotypes) these genes sometimes assort independently they must linked: on the same chromosome but the linkage is incomplete: cross-over sometimes creates recombinant chromosomes Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Morgan: experiments with fruit flies Interested in how linkage (when characters are on the same chromosome) affects inheritance of two characters crossed flies that differed in traits of body color and wing size Conclusions: body color and wing size are usually inherited together in specific combinations (parental phenotypes) these genes sometimes assort independently they must linked: on the same chromosome but the linkage is incomplete: cross-over sometimes creates recombinant chromosomes Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Morgan: experiments with fruit flies Interested in how linkage (when characters are on the same chromosome) affects inheritance of two characters crossed flies that differed in traits of body color and wing size Conclusions: body color and wing size are usually inherited together in specific combinations (parental phenotypes) these genes sometimes assort independently they must linked: on the same chromosome but the linkage is incomplete: cross-over sometimes creates recombinant chromosomes Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Morgan: experiments with fruit flies Interested in how linkage (when characters are on the same chromosome) affects inheritance of two characters crossed flies that differed in traits of body color and wing size Conclusions: body color and wing size are usually inherited together in specific combinations (parental phenotypes) these genes sometimes assort independently they must linked: on the same chromosome but the linkage is incomplete: cross-over sometimes creates recombinant chromosomes Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Morgan: experiments with fruit flies Interested in how linkage (when characters are on the same chromosome) affects inheritance of two characters crossed flies that differed in traits of body color and wing size Conclusions: body color and wing size are usually inherited together in specific combinations (parental phenotypes) these genes sometimes assort independently they must linked: on the same chromosome but the linkage is incomplete: cross-over sometimes creates recombinant chromosomes Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Morgan: experiments with fruit flies Interested in how linkage (when characters are on the same chromosome) affects inheritance of two characters crossed flies that differed in traits of body color and wing size Conclusions: body color and wing size are usually inherited together in specific combinations (parental phenotypes) these genes sometimes assort independently they must linked: on the same chromosome but the linkage is incomplete: cross-over sometimes creates recombinant chromosomes Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
Recombination Modeling Build your diploid cell (an homologous pair for each chromosome) Draw a big cell with a nucleus inside. DRAW homologous pairs of chromosomes: 1 big blue, 1 big red 1 small blue, 1 small red Add genes to your chromosome Write an H and an R on big blue, and an h and an r on big red Write a T on small blue, and a t on small red Clone each chromosome (DNA Replication) (making sister chromatids) Nucleus breaks down (erase it). Homologous pairs form a tetrad: crossing over may occur. (note: do not model crossing over for now) Finish meiosis: (see notes for help) Nucleus "grows" around chromosomes. 4 cells made (gametes, which have half the number of chromosomes (haploids) Repeat Steps #1-6, this time at Step 4, include ONE crossover event. When you’re confident on the process, show Mr. Jones.
Recombination Modeling When you’re confident on the process, show Mr. Jones. In your notebook: Figure 15.10: Recombination: p.295 At each stage, describe what is happening in 1-2 sentences. DO NOT COPY DRAW with LABELS: cell membrane nucleus chromosome DNA replication cytokinesis sister chromatid crossing over recombinant chromosome independent assortment Meiosis I Meiosis II
Recombination Modeling Analysis How does recombination increase the variety of gametes formed? Which types of gametes were more likely? Gametes with recombinant chromosomes or ones without? Recombination is a random process. How might it benefit/hurt the survival of an individual/species?
How could you calculate recombination frequency? Warm-UP: How could you calculate recombination frequency? What would the recombination frequency tell you about the relative position of genes on a chromosome? Genes A, B, and C are on the same chromosome. Testcrosses show that the recombination frequency between A and B is 28% and between A and C is 12%. Can you determine the linear order of these genes? Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? Homework DUE Tomorrow: Linked and Unlinked Genes DUE Tonight: Monohybrid Crosses to turnitin.com DUE Friday: Dihybrid Crosses to turnitin.com DUE Now: 15.3 UNIT 7/8 TEST: March 19th Inheritance and Regulation
Inheritance and Regulation Warm-UP: Talk about your Concept Check with your table team. Do you have agreement? Do you have questions? Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? Homework DUE Tomorrow: Linked and Unlinked Genes DUE Tonight: Monohybrid Crosses to turnitin.com DUE Friday: Dihybrid Crosses to turnitin.com DUE Now: 15.3 UNIT 7/8 TEST: March 19th Inheritance and Regulation
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Sturtevant: Genetic Mapping linkage map: an ordered list of the genetic loci along a particular chromosome based on recombination frequencies map unit one map unit: represents a 1% recombination frequency indicate relative distance and order, not precise locations of genes 50% frequency of recombination is observed for any two genes on different chromosomes the farther apart two genes are, the higher the probability a crossover will occur between them and therefore the higher the recombination frequency genes that are far apart on the same chromosome can have a recombination frequency near 50%. Such genes are physically linked, but genetically unlinked, and behave as if found on different chromosomes Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Sturtevant: Genetic Mapping linkage map: an ordered list of the genetic loci along a particular chromosome based on recombination frequencies map unit one map unit: represents a 1% recombination frequency indicate relative distance and order, not precise locations of genes 50% frequency of recombination is observed for any two genes on different chromosomes the farther apart two genes are, the higher the probability a crossover will occur between them and therefore the higher the recombination frequency genes that are far apart on the same chromosome can have a recombination frequency near 50%. Such genes are physically linked, but genetically unlinked, and behave as if found on different chromosomes Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Abnormal Chromosome Number In nondisjunction, pairs of homologous chromosomes do not separate normally during meiosis As a result, one gamete receives two of the same type of chromosome, and another gamete receives no copy Aneuploidy results from the fertilization of gametes in which nondisjunction occurred Offspring with this condition have an abnormal number of a particular chromosome Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. Abnormal Chromosome Number In nondisjunction, pairs of homologous chromosomes do not separate normally during meiosis As a result, one gamete receives two of the same type of chromosome, and another gamete receives no copy Aneuploidy results from the fertilization of gametes in which nondisjunction occurred Offspring with this condition have an abnormal number of a particular chromosome Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
Warm-UP: What can we learn about inheritance from looking at a pedigree? (use example of the Royal Family of Europe from the early 1900s) Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? UNIT 7/8 TEST: March 19th Inheritance and Regulation DUE Linked vs Unlinked Genes: 15.3 DUE Tonight: Dihybrid Crosses to turnitin.com
Warm-UP: In the following human pedigree, squares represent males, circles represent females, and shaded symbols indicate individuals affected with a disorder. One of the affected males from the third generation has a child with a female who is a carrier. For the pedigree shown, which of the following best expresses the probability that the couple’s first son will be affected with the disorder? (A) 25% (B) 50% (C) 75% (D) 100% Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? UNIT 7/8 TEST: March 19th Inheritance and Regulation DUE Linked vs Unlinked Genes: 15.3 DUE Tonight: Dihybrid Crosses to turnitin.com
Is a widow’s peak a dominant or recessive trait? Figure 14.15 Pedigree analysis
Is a widow’s peak a dominant or recessive trait? Figure 14.15 Pedigree analysis
George Arlene Sandra Tom Sam Wilma Ann Michael Carla Daniel Alan Tina Fig. 14-UN5 George Arlene Sandra Tom Sam Wilma Ann Michael Carla Daniel Alan Tina Christopher
#1 A heterozygous tall and a homozygous purple flowered plant is crossed with a short and white flowered plant. Predict the offspring. Assume independent assortment Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? P=purple p=white T=tall t=short
#2 For a plant with the genotype WwXxYyZz, what is the probability that the plant will produce a gamete with a haploid genotype of Wxyz ? Give your answer as a fraction or as a value between 0 and 1, to four decimal places. Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
#3 A completely-plated stickleback from a marine population was mated to a low-plated stickleback from a freshwater population. The resulting F1 hybrids all displayed a completely plated phenotype. When the F1 hybrids were allowed to interbreed, the resulting F2 generation included completely plated offspring and low-plated offspring in an approximate 3:1 ratio. Which of the following conclusions is best supported by the results of the breeding experiments? Phenotypic variation in the F2 generation suggests that armor morphology is controlled by many alleles of a single gene. The completely-plated phenotype is controlled by a dominant allele of a single gene. Armor loss is an acquired characteristic that is affected by one or more environmental factors. Patterns of armor plating in stickleback populations are regulated by sex-specific signals. Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
#4 If a man with type AB blood marries a woman with type O, what blood types would you expect in their children? What fraction would you expect of each type? Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? IA= Type A IB= Type B i= Type O
#5 If a King marries a Queen that is a carrier of hemophilia (sex-linked recessive disease that is historically fatal before adulthood), what is the chance of the Kingdom having an heir to the king’s throne, assuming only one child is born? Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
#6 Is an attached earlobe a dominant or recessive trait? Draw the pedigree and fill in the genotypes for each offspring. Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
#6 Is an attached earlobe a dominant or recessive trait? Draw the pedigree and fill in the genotypes for each offspring. Figure 14.15 Pedigree analysis
Gregor Mendel’s pioneering genetic experiments with pea plants occurred before the discovery of the structure and function of chromosomes. Which of the following observations about inheritance in pea plants could be explained only after the discovery that genes may be linked on a chromosome? #7 Pea color and pea shape display independent inheritance patterns. Offspring of a given cross show all possible combinations of traits in equal proportions. Most offspring of a given cross have a combination of traits that is identical to that of either one parent or the other. Recessive phenotypes can skip a generation, showing up only in the parental and F 2 generations. Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation?
Table I shows the results of breeding experiments to examine the inheritance of flower color (purple versus white) and pod shape (inflated versus constricted). For the crosses recorded in Table I, true-breeding parents were crossed to produce F1 offspring, which were then testcrossed to homozygous recessive individuals. Table II shows the results of computer-simulated crosses to model the inheritance of leaf shape (broad versus narrow) and flower color (purple versus white). Based on the data in Table I, which of the following best explains why there are no individuals with constricted pods in the F 1 generation? Inflated pod shape is dominant to constricted pod shape. The inflated-pod offspring in the F sub one generation are homozygous. Constricted pod shape typically arises from a new mutation in the F 1 generation. The constricted-pod offspring are carriers for the inflated pod shape allele. Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? #8
Table I shows the results of breeding experiments to examine the inheritance of flower color (purple versus white) and pod shape (inflated versus constricted). For the crosses recorded in Table I, true-breeding parents were crossed to produce F1 offspring, which were then testcrossed to homozygous recessive individuals. Table II shows the results of computer-simulated crosses to model the inheritance of leaf shape (broad versus narrow) and flower color (purple versus white). In Table I, the ratio of phenotypes in the offspring from the testcross with F 1 plants that had purple flowers and inflated pods suggests that the genes for flower color and pod shape are located close together on the same autosome on the X chromosome on different chromosomes on a mitochondrial chromosome Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? #9
Table I shows the results of breeding experiments to examine the inheritance of flower color (purple versus white) and pod shape (inflated versus constricted). For the crosses recorded in Table I, true-breeding parents were crossed to produce F1 offspring, which were then testcrossed to homozygous recessive individuals. Table II shows the results of computer-simulated crosses to model the inheritance of leaf shape (broad versus narrow) and flower color (purple versus white). Which of the following provides the best justification for an assumption that might have been used in the computer simulation (Table II)? The broad allele is recessive to the narrow allele because broad leaves appear in every generation. The purple allele is dominant to the white allele because all the offspring from the cross of purple-flowered and white-flowered plants had purple flowers. The narrow allele is codominant with the purple allele because the purple-flower trait and the narrow-leaf trait segregate together. The white allele is dominant to both the broad and narrow alleles because plants with either type of leaf shape can have white flowers. Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? #10
Table I shows the results of breeding experiments to examine the inheritance of flower color (purple versus white) and pod shape (inflated versus constricted). For the crosses recorded in Table I, true-breeding parents were crossed to produce F1 offspring, which were then testcrossed to homozygous recessive individuals. Table II shows the results of computer-simulated crosses to model the inheritance of leaf shape (broad versus narrow) and flower color (purple versus white). In Table II, the F 1 offspring of the cross between broad-leaved, white-flowered plants with narrow-leaved, purple-flowered plants have a phenotype that differs from that of either parent. However, many testcross offspring have the same phenotype as one of the two plants in the parental cross, but relatively few testcross offspring have the same phenotype as the F 1 offspring. Which of the following best explains the observation? Recombination between the leaf-shape and flower-color genes resulted in chromosomes carrying a dominant allele of both genes. Recombination between the broad and narrow alleles of the leaf-shape gene resulted in chromosomes carrying three different alleles at the same genetic locus. Independent assortment of homologous chromosomes resulted in the combinations of alleles present in the parental generation. The computer model cannot capture the possible assortments of gametes when multiple genes are considered. Figure 14.3 When F1 hybrid pea plants are allowed to self-pollinate, which traits appear in the F2 generation? #11