Presentation on theme: "Genetics How do traits pass from parents to offspring?"— Presentation transcript:
Genetics How do traits pass from parents to offspring?
Genetics Unit Create a vocabulary sheet. Through-out these notes, write any “red” vocabulary words and their definitions on this page. Vocabulary WordDefinition: p
DNA Chromosomes From Chromosome to DNA How DNA is packaged animation Meiosis is how DNA is copied and sepereted to make gametes (sperm and egg)
Complete cornell notes for the Meiosis videoMeiosis video What is the purpose of Meiosis and Mitosis? p
Complete the lab “Why don’t we look like our siblings” p
Traits Alleles Inheritance Gregor Mendel – “Father of Genetics” Did experiments with pea plants in mid-late 1800’s to show basic patterns of inheritance Seed Shape (round or wrinkled) Seed Color (yellow or green) Seed Coat color (gray or white) Pod Shape (smooth or constricted) Pod Color (green or yellow) Flower Position (axial or terminal) Plant Height (tall or short) Found that when two plants with different alleles are crossed, the offspring look like one of the parents, rather than a blending of both parents. Principle of Dominance Some alleles are dominant and others are recessive Dominant Alleles Recessive Alleles
Linked genes (genes that occur very close to one another on a chromosome) are the exception Write these 4 ideas from Mendel Summary of Mendel’s Principles Phenotype song Phenotype song Gregor Mendel’s work forms the basis of modern genetics: Genes are passed from parent to offspring Some forms of genes (alleles) are dominant while others are recessive Genes randomly segregate (independent assortment) when gametes are formed The alleles for different genes usually segregate independently of one another p
Inheritance: the passing of traits from parents to offspring Gregor Mendel – “Father of Genetics” Phenotype - The observable physical characteristic of a trait Genotype - The genetic combination of alleles for a trait Punnett Square – tool used to predict probability of phenotype Notice that letters are used to represent the alleles (usually correspond to the dominant phenotype – e.g. “P” for purple) Upper Case Letters = Dominant Allele Lower Case Letters = Recessive Allele Phenotype: White Genotype: pp Phenotype: Purple Genotype: PP
Practice Overview of genes to traits video Copy the 3 questions below: What do they mean when they say “you have your father’s hair”? How many chromosomes do organisms have? How much DNA do we have in common with other animals? p
Complete the “Just Like Me” lab. p
Just like Me Widow’s Peak (P)No Widows peak (p)
Just Like Me Dimples (D)No Dimples (d)
Just Like Me Freckles (F)No Freckles (f)
Just Like Me PTC Taster (J)PTC nontaster (j)
Just Like Me Hand cross Right thumb on top (A) Hand cross Left thumb on top (a)
Just Like Me “Bent” Little fingers (B)Parallel little fingers (b)
Just Like Me Tongue roller (T)Non-tongue roller (t)
Just Like Me Hair on fingers (H)No hair on fingers (h)
Just Like Me Free ear lobe (unattached) (E)Attached ear lobe (e)
Just Like Me Cleft (dimpled) chin (C)No cleft chin (c)
Just Like Me PREDICTION For each trait, make a prediction about what percentage of your classmates are “like you” for each trait.
Just Like Me results Go to your teachers website Click on the phenotype survey link Fill in your results Use the “form” button on the top menu bar to show the class results finish Fill in the chart on your paper Make a bar graph of the results Answer all the questions p
Inheritance Gregor Mendel – “Father of Genetics” Found that alleles show up in predictable patterns and that some alleles show up more often than others Homozygous (Pure-Breeds) - both alleles are the same Heterozygous (Hybrids) - both alleles are different Carriers – heterozygotes for a recessive trait Pure-Breed Crosses result in: 100% chance dominant phenotype Hybrid Crosses result in: 75% chance dominant phenotype 25% chance recessive phenotype
Inheritance Gregor Mendel – “Father of Genetics” Found that alleles show up in predictable patterns and that some alleles show up more often than others Alleles can be tracked through multiple generations and probabilities determined First Generation: First Filial (F1) 100% chance dominant phenotype Second Generation: Second Filial (F2) 75% chance dominant phenotype Third Generation: Third Filial (F3) 63% chance dominant phenotype 100% chance 75% chance 0% chance Parents: P1 generation
Practice Dominant vs Recessive genes video Video on making punnett squares Complete the Probability (Long vs Short Big Toe) Lab. p
Solving Punnett Squares : If a round pea plant (AA) is crossed with a wrinkled pea plant (aa), what percent of the offspring will be: Round? Wrinkled? If two heterozygous round pea plants are crossed, what percent of the offspring will be: Round? Wrinkled? If a heterozygous round pea plant is crossed with a homozygous wrinkled pea plant, what percent of the offspring will be: Round? Wrinkled? p
Complete dominance 1.Which of the following are genotypes and which are phenotypes: Brown hairHomozygous recessive BbWebbed Fingers Hybrid Down Syndrome 2. If two individuals mate and their child has a phenotype completely different from both parents, what was the genotype of the parents? p86p
Codominance If two alleles are codominant and two heterozygous (spotted RW) flowers mate, what percentage of the offspring will have white flowers (WW) and what percentage will have red flowers (RR)? p
Complete Dominance Codominance Homozygous genotype one phenotype Heterozygous genotype both phenotypes Incomplete Dominance Sex-Linked Polygenic Traits Phenotypic Expression Varies R1 R1 R2 R1R2 R1R2 R R W RW RW
Practice Intro to blood types (first 3 minutes good) Complete blood typing handout p
Blood type of parents All possible genotypes of parent All possible genotypes of children All possible blood types of children Blood types not possible for children A and O B and O A and B AB and A AB and B AB and O O and O p
Complete Dominance Codominance Incomplete Dominance Sex-Linked X-linked: gene lies on X chromosome (males only have one copy of the gene) Y-linked: gene lies on Y chromosome (only males have the gene) Contributes to younger mortality rate in males Polygenic Traits
Practice Pipe Cleaner babies and genetic traits”. X-linked Inheritance worksheet p
Solving Punnett Squares Depending on how the chromosomes independently assort determines the genotype, and thus phenotype, of the resulting progeny (offspring) Parents Offspring Predicting phenotype gets more complicated when you look at more than one trait at a time
Practice Dihybrid Crosses handout (bunny rabbits). And Sponge Bob II p
Solving Punnett Squares : If a round, yellow pea plant (AABB) is crossed with a wrinkled, green pea plant (aabb), what percent of the offspring will be: Round and yellow? Round and green? Wrinkled and yellow? Wrinkled and green? What about the F2 generation? p
Pedigree Rules What is a pedigree? *A pedigree is a chart that shows all family members and how they are related. It follows certain rules and shows genotypes and phenotypes. p
–BoysShaded- Phenotype being “traced” –Girls X deceased Marriagesame level=same generation Mating w/o marriageCarrier (heterozygous) KidsAdopted Twins
Draw a pedigree for your immediate family (mom, dad, step parents, siblings, etc)
More Practice Pedigree project p
Pedigrees Autosomal Dominant Pedigree How can we tell? Graphically shows the lineage of a disorder in a particular family Be able to tell if disorder is dominant, recessive, or sex- linked from a pedigree Be able to predict the chance that an indicated couple will have a child with the disorder
Pedigrees Autosomal Recessive Pedigree How can we tell? Graphically shows the lineage of a disorder in a particular family Be able to tell if disorder is dominant, recessive, or sex- linked from a pedigree Be able to predict the chance that an indicated couple will have a child with the disorder
Pedigrees Graphically shows the lineage of a disorder in a particular family Be able to tell if disorder is dominant, recessive, or sex- linked from a pedigree Be able to predict the chance that an indicated couple will have a child with the disorder Sex-Linked Pedigrees How can we tell? Is the X-linked dominant or recessive?
Pedigree Analysis Case Study Read family information Put family name at the top of your whiteboard Make a pedigree for the entire family Place name of condition under family name Label names of all family members that you know Make a key for the possible genotypes and phenotypes of your trait. Label as many individual genotypes on the pedigree that you can. Shade in the people that have the trait Identify the Patterns in the Pedigree and write the answers on your whiteboard: Does the trait: – show up in every generation? –Or, does the trait skip a generation? Is the trait dominant or recessive? Gender: –Does the trait affect males/females equally? –Or, Does the trait only affect males? Or, only females? Does your trait fit one of the patterns we have learned so far (complete dominance, codominance, incomplete dominance, or X-linked)? If so, which one? How do you know? p
More Practice Hooded Murderer
Karyotypes Complete the karyotype webquest p
More practice: Oompa Loompa Genetics p
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Step 1: Fill in Table of Alleles for your paper bag pet that reflect its genotype for each trait. Note that Tail and Eyelashes are X-Linked! T RAIT S YMBOLS FOR E ACH A LLELE P HENOTYPE G ENOTYPE SexXX or XY Nose ShapeCircle (N), Triangle (n) Eye ShapeSlit (E), Oval (e) Ear ShapeRound (R), Pointed (r) Hair ColorBlack (H), Brown (h), yellow (y) Eye ColorBrown (B), Blue (b), green (g), yellow (y) EyelashesEyelashes (L), No Eyelashes (l) X- linked! TailTail (T), No Tail (t) On Y chromosome- only males can have a tail!
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Step 2: Decorate a “pet” paper bag with traits that adhere to this given set of phenotype choices: Cut off the bottom 1” from the paper bag. Use this strip to make arms and other body parts. Gendermale or female? Tailtail or no tail? (females cannot have tails) Eye Shaperound or oval (almond) shaped? Eye Colorbrown, blue, green, yellow? Eyelasheshas eyelashes or is lashless? Nose Shapecircular or triangular? Hair Colorblack, brown, or yellow? Ear Shaperound or pointed?
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Step 3: Create chromosomes for your paper bag pet that reflect its genotype for each trait For Females
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Create chromosomes for your paper bag pet that reflect its genotype for each trait For Males
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Step 4: Create gametes for your pet paper bag Step 1: DNA replication For Males For Females
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Create gametes for your pet paper bag Random assortment Crossing Over Step 2: Crossing Over Step 3: Random Assortment Step 4: First cell division
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Create gametes for your pet paper bag Step 5: Second cell division
STEP 5: Carefully cut out the parent chromosomes and glue them onto the back side of your parent bag (these are the DARK chromosomes). Also cut and glue the parent table of alleles to the bag.
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Step 6: Find a mate and procreate! Trade one autosome and one sex chromosome with someone else. These are your child’s chromosomes. Glue them onto the back of a new bag.
Step 7: Fill out a table of alleles for your child from the child’s chromosomes. –Glue the table onto your new paper bag next to the chromosomes. Step 8: decorate your child. Step 9: Fill out a birth certificate for your child. MomChild
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun!
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Step 10: Fill out the Punnett Square Worksheet
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Fill out the Punnett Square Worksheet
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Fill out the Punnett Square Worksheet
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! 1.Fill in Table of Alleles and create chromosomes for your paper bag pet that reflect its genotype for each trait 2.Decorate a “pet” paper bag with traits that adhere to a given set of phenotype choices 3.Create gametes for your pet paper bag 4.Find a mate and procreate 5.Fill out the Punnett square worksheet to predict the traits of your offspring 6.Give birth: decorate your baby bag with phenotypes that match its genotypes and fill out the birth certificate
Paper Bag Pets: A Genetics Project Making Genetics Easy and Fun! Day 1 Decorate a “pet” paper bag with traits that adhere to a given set of phenotype choices Day 2 Create chromosomes for your paper bag pet that reflect its genotype for each trait (use rest of period to introduce or reinforce meiosis) Day 3 Create gametes for your pet paper bag Day 3 Find a mate and procreate Day 4 Fill out the Punnett square worksheet to predict the traits of your offspring (first introduce or reinforce Mendelian genetics) Day 5 Give birth: decorate your baby bag with phenotypes that match its genotypes and fill out the birth certificate Method 1: Culminating Project
Mitosis vs Meiosis Nova Videos Cracking the Code of Life: Miracle of Life: Tay Sachs (one wrong letter) Animations
Practice Problems 1.How do mutations during meiosis affect an organism differently than mutations during mitosis? 2.At each step of meiosis, is the cell haploid or diploid? 3.Which of the following are genotypes and which are phenotypes: Brown hairHybrid BbWebbed Fingers Homozygous recessiveDown Syndrome 4.If an allele is dominant and two heterozygous individuals mate, what is the chance that their child will have the dominant phenotype? 5.If two alleles are codominant and two heterozygous individuals mate, what is the chance that their child will have both phenotypes? 6.If two individuals mate and their child has a phenotype completely different from both parents, what was the genotype of the parents? 7.If a disorder is X-linked and a normal man mates with a woman who is a carrier, what is the chance that they will have a boy with the disorder? What is the chance that they will have a girl with the disorder?
Practice Problems 8.If a woman is homozygous recessive for both blonde hair and blue eyes and she mates with a man who is heterozygous for both brown hair and brown eyes, what is the chance that their child will have blonde hair and blue eyes? 9.In real life, eye color and hair color are actually polygenic in humans. What does this mean? 10.If a person with type A blood mates with a person with type AB blood, what is the chance that they will have a child with: type A blood? type B blood? type AB blood? 11.If a person with type O blood mates with a person with type AB blood, what is the chance that they will have a child with: type O blood? type A blood? type AB blood? type B blood?
Practice Problems 12.In the pedigree, which individuals are affected males? Affected females? Normal males? Normal females? 13.Which type of inheritance is indicated by the pedigree below? 14.Which individuals are homozygous recessive in the pedigree? 15.Which individuals are homozygous dominant in the pedigree? 16.Which individuals are heterozygous in the pedigree? 17.If the top two individuals in the pedigree had another baby, what are the chances that he/she would have the disorder?
1.Which regulatory mechanisms occur at the DNA-level, which occur at the protein-level? 2.How do acetylation, methylation, repressors, activators, and siRNA control gene expression? What role do inducers play? 3.What is an enhancer and how does it help control how much of a particular protein is made? 4.How do allosteric inhibition and competitive inhibition differ in the ways they accomplish feedback inhibition? 5.What are the three phases of the cell cycle? What occurs at each phase? 6.What are the four phases of mitosis? What occurs at each phase? 7.What are cell cycle checkpoints? Why are they important? 8.What is apoptosis? What role does it play in the cell cycle? 9.What is the difference between chromatin and chromosomes? 10.What is the role of the centromere? (What would happen without it?) Practice Questions
11.What is the difference between a chromatid and a chromosome? 12.What events must happen in order for two sister chromatids to separate from one another and move to opposite sides of the cell? (What happens at the centromere? What happens to the centromere? What is the role of the mitotic spindle?) 13.What would happen if two sister chromatids moved to the same side of the cell? 14.What happens to the mitotic spindle after mitosis? 15.What are gametes? Where are they made in the body? How are they made? 16.What are the eight phases of meiosis? What occurs during each phase? How does meiosis differ from mitosis? 17.How do crossing over and random assortment “mix up” genes so that children are genetically different from their parents? 18.Why are insertion and deletion mutations usually more harmful than substitution mutations? Practice Questions
19.How does nondisjunction affect the genes present in an organism? Specifically, why does it cause deformities? 20.What “super powers” must a cell acquire to become cancerous? How does it acquire these powers? 21.Compare and contrast oncogenes and tumor suppressor genes. What are they? How are they similar? How are they different? 22.Why is cancer primarily a disease of old age? 23.How do mutations cause genetic variation? Is this good or bad for the organism? 24.How do genetic diseases caused by point mutations differ from those caused by chromosomal mutations like nondisjunction? 25.What causes spontaneous mutations? What causes induced mutations? 26.How accurate is DNA replication? (That is, how often do point mutations occur?) 27.What type of mutation is shown here? AGTGCCGTCAC TCACGGCCAGTG Practice Questions
28.Why is DNA synthesis said to be “semiconservative”? 29.What role do DNA polymerase, DNA primase (a type of RNA polymerase), helicase, topoisomerase, RNase H, and ligase play in DNA replication? 30.What is the difference between how the leading strand and lagging strand are copied during DNA replication? Why do they have to be synthesized differently in this fashion? 31.What would happen if insufficient RNase H were produced by a cell? What if insufficient ligase were produced by a cell? 32.What are four key differences between DNA polymerase and RNA polymerase? (“they are difference molecules” doesn’t count as one!) 33.Compare and contrast codons and anticodons? 34.What is alternative splicing? Why is it necessary in eukaryotes? 35.During translation, what amino acid sequence would the following mRNA segment be converted into: AUGGACAUUGAACCG? 36.How come there are only 20 amino acids when there are 64 different codons? 37.How come prokaryotes can both transcribe and translate a gene at the same time, but eukaryotes cannot? Practice Questions
Sources of Genetic Diversity During Interphase (DNA Replication) Mutations – create new alleles During Meiosis Random Assortment (Independent Alignment) – mixes up chromosomes inherited from mother and father Crossing Over – mixes up genes that occur on the same chromosome (“Linked genes” occur adjacent or very close to one another on the same chromosome and so are almost always inherited together) During Sex Fertilization – mixes up genes from two different partners
Inherited (from mom or dad or both) New Mutations (“De Novo”) (new point mutations or chromosomal) Genetic Disorders Gametes (egg / sperm) meiosis Complete Dominance Incomplete Dominance Codominance Sex-Linked Polygenic Traits Tay Sachs (one wrong letter)
Variations in Heritability Qualitative Traits controlled by a single gene Clearly have a defined phenotype Ex: attached ears or lobed ears Qualitative Traits Controlled by multiple genes (polygenic) Influenced by the environment Shows a gradation of phenotypes Ex: height
Polymerase Chain Reaction (PCR) Method used to copy DNA 1.Strands are “melted” apart using heat 2.Primers and nucleotides (NTP’s) are added and the mix is gradually cooled 3.Results in formation of complementary strands 4.Cycle is repeated, doubling number of DNA strands each time
Complete Dominance Codominance Incomplete Dominance Sex-Linked Polygenic Traits Controlled by more than one gene Most common type of expression Phenotypic Expression Varies