2. 2 Types of Cells Recall that there are two types of cells in multicellular organisms Recall that there are two types of cells in multicellular organisms –Somatic cells- all body cells (liver, lungs, etc.) with the exception of sex cells –Gametes- sex cells such as egg and sperm which are responsible for passing on our genes

3. Chromosomes The somatic cells of each species has a characteristic number of chromosomes per cell The somatic cells of each species has a characteristic number of chromosomes per cell Chromosome number is not related to complexity Chromosome number is not related to complexity –A type of fern has 1200 –Fruit flies have 8 –Humans have 46

4. Karyotypes How did we learn this information about human chromosomes? How did we learn this information about human chromosomes? –Karyotypes- pictures of the chromosomes from a somatic cell –This shows normal humans have 46 chromosomes

5. Human Cells  Human somatic cells are diploid-chromosomes are in pairs (23 pairs for humans=46)  Human gametes, egg and sperm, are haploid-no pairs (only 23 single chromosomes) 

6. Homologous Chromosomes Homologous chromosomes— pairs of chromosomes in somatic cells that have the same length and same types of genes Homologous chromosomes— pairs of chromosomes in somatic cells that have the same length and same types of genes In each of our 23 pairs In each of our 23 pairs –our mom’s egg contributed one chromosome –our dad’s sperm contributed the other Homologous Chromosomes Note the numbering system for the homologous pairs

7. Types of Chromosomes There are two types of chromosomes There are two types of chromosomes –Autosomes- the chromosomes pairs 1-22 whose DNA codes for characteristics not directly related to the sex of the organism –Sex chromosomes- the 23 rd pair (X, Y) in humans that have genes that directly control the development of sexual characteristics  XX female  XY male

8. Cell Division 1. Binary fission-cell division in prokaryotes 1. Binary fission-cell division in prokaryotes 2. Cell Cycle (with Mitosis)-cell division in eukaryotes to form new somatic cells 2. Cell Cycle (with Mitosis)-cell division in eukaryotes to form new somatic cells 3. Meiosis—cell division in eukaryotes to form gametes (egg and sperm) 3. Meiosis—cell division in eukaryotes to form gametes (egg and sperm)

9. How Are Gametes Formed?  Meiosis--cell division that produces sex cells called gametes from somatic cells in testes and ovaries 1 REPLICATION AND 2 DIVISIONS 46 chromosomes ----------  23 chromosomes 1 REPLICATION AND 2 DIVISIONS 46 chromosomes ----------  23 chromosomes diploid (pairs) MEIOSIS haploid (no pairs) diploid (pairs) MEIOSIS haploid (no pairs) 1 somatic (body) cell 4 gametes (sex cells) START END START END

10. HAPLOID GAMETE (EGG) 23 CHROMOSOMES + = HAPLOID GAMETE (SPERM) 23 CHROMOSOMES FIRST DIPLOID SOMATIC CELL OF BABY 46 CHROMOSOMES IN PAIRS!!!!

11. With meiosis cells go from 46  23 chromosomes With meiosis cells go from 46  23 chromosomes and the result is: and the result is: your mom’s egg (23 chromosomes) your mom’s egg (23 chromosomes) + your dad’s sperm (23 chromosome) first cell of you (46 chromosomes) first cell of you (46 chromosomes) WITHOUT MEIOSIS to go from 46  23 chromosomes then it would be…… WITHOUT MEIOSIS to go from 46  23 chromosomes then it would be…… your mom’s egg (46 chromosomes) + your dad’s sperm (46 chromosomes) 92 AND NO YOU!!!!!!!!!! 92 AND NO YOU!!!!!!!!!!

13. 46 23 Spermatogonium in testes SPERM

14. 46 23 Oogonium in ovaries Polar Bodies (not functional) Egg

15. 23 46 23 46 testes cell ovary cell sperm produced by meiosis fertilization zygote ova (egg) produced by meiosis but only one develops to maturity

16. 46 Cell division continues by the cell cycle (with mitosis), so all the cells will contain 46 chromosomes early embryo 16

17. Genetic Diversity in Gametes There is great genetic diversity of the egg and sperm one parent can make due to two processes that occur during meiosis There is great genetic diversity of the egg and sperm one parent can make due to two processes that occur during meiosis –Crossing-over-chromosomes cross and exchange pieces –Independent assortment- chromosomes of each pair are randomly distributed to each egg or sperm –Independent assortment and gamete diversity Independent assortment and gamete diversityIndependent assortment and gamete diversity

19. Genetics Genetics-study of inherited traits Genetics-study of inherited traits Heredity-passing of traits from parents to offspring Heredity-passing of traits from parents to offspring Trait-feature of an organism that can be passed on to offspring Trait-feature of an organism that can be passed on to offspring ex) hair color, eye color, etc

20. What Determines Traits? Genes! Genes! Genes-segments of Genes-segments of DNA on chromosomes that code for a protein which produces a trait There are 1000’s of There are 1000’s of genes on each chromosome genes on each chromosome Gene  Protein  Trait Gene  Protein  Trait

21. Traits Some traits are coded for by one gene which codes for one protein causing a trait. Some traits are coded for by one gene which codes for one protein causing a trait. –i.e. freckles, earlobe attachment, etc protein

22. Height is a polygenic trait Polygenic traits – traits coded for by many genes together More than one gene=more than one protein that causes the trait so complex variation in that trait Hand span, height, eye color, etc. Traits

23. Your Cells Have Two Copies Recall that your chromosomes are in pairs: Recall that your chromosomes are in pairs: –Mom contributed one and Dad contributed other of each pair –This means each somatic cell has two copies of each chromosome, and therefore, each gene –So when we talk about your genes, we must consider BOTH copies you received

24. Alleles The same gene can have many versions The same gene can have many versions Alleles - forms of genes written as letters Alleles - forms of genes written as letters –F  allele codes for freckles –f  allele codes for no freckles Allele for freckles--F Allele for no freckles—f Position on chromosomes where freckle presence gene is located

25. A B C D E F G H I a b c d e f g h I FROM FROM MOM DAD ONE OF YOUR CHROMSOME PAIRS FRECKLE GENE IN ADDITION TO MANY OTHERS

26. Genotype vs. Phenotype Genotype- the genetic Genotype- the genetic makeup of an organism –Written as 2 letters-one copy from each parent –FF, Ff, or ff Phenotype- the physical traits Phenotype- the physical traits the organism shows –Written as descriptive words –Freckles or no freckles ***Phenotype = Genotype + Environment

27. Genotypes Homozygous genotype- (purebred) receiving two identical alleles for a particular trait from your parents Homozygous genotype- (purebred) receiving two identical alleles for a particular trait from your parents –i.e. Freckle presence gene –Alleles F=freckles and f=none –Homozygous: FF or ff Heterozygous genotype – (hybrid) receiving two different alleles for a particular trait from your parents Heterozygous genotype – (hybrid) receiving two different alleles for a particular trait from your parents –Heterozygous: ________?

28. Genotypes Homozygous genotype- (purebred) receiving two identical alleles for a particular trait from your parents Homozygous genotype- (purebred) receiving two identical alleles for a particular trait from your parents –i.e. Freckle presence gene –Alleles F=freckles and f=none –Homozygous: FF or ff Heterozygous genotype – (hybrid) receiving two different alleles for a particular trait from your parents Heterozygous genotype – (hybrid) receiving two different alleles for a particular trait from your parents –Heterozygous: ____Ff____?

29. F FFf ff Mom Dad Mom Dad Mom Dad Possibility #1 Possibility #2 Possibility #3

30. What About the Heterozygous Genotype? FF genotype = ____________ phenotype? FF genotype = ____________ phenotype? ff genotype = _____________phenotype? ff genotype = _____________phenotype? What about Ff phenotype? What about Ff phenotype? –As it turns out, the allele coding for freckles, F, dominates over the alleles coding for no freckles, f. –The heterozygous genotype, Ff, results in a round phenotype, (freckles)

31. Dominant allele – form of trait that overcomes others and written as a capital letter-i.e. F Recessive allele—form of trait that is hidden in the presence of a dominant one and written as a lower case letter-i.e. f F FFf ff Mom Dad Mom Dad Mom Dad

32. GenotypeExamplePhenotype Homozygous Dominant Freckles No freckles Heterozygous

33. GenotypeExamplePhenotype Homozygous Dominant FFFreckles Homozygous Recessive ffNo freckles HeterozygousFfFreckles

34. So What? How can we use this information on meiosis and genetics? How can we use this information on meiosis and genetics? –If we know parents’ genotypes, we can figure out the genotype possibilities of their children –It can be used to determine how likely you and your spouse are to have children with freckles, their blood type, or the possibility of passing on a disease to them among other things

35. Genetics Predictions To determine possible genotypes of offspring, we use Punnett squares To determine possible genotypes of offspring, we use Punnett squares –Punnett squares -figures used to determine genotype and phenotype probabilities of offspring based on the parents’ genotypes. –For example, if you crossed two heterozygous parents who have freckles, would their kids all have freckles, just some, or none at all? Ff Parent #2 gametes Ff Parent #1 gametes

36. Practice Trait: Number of fingers Alleles: F or f Dominant: F codes for polydactyly so person has more than 5 fingers or toes. Recessive: f codes for normal five fingers or toes

37. GenotypeExamplePhenotype Homozygous Dominant FF Homozygous Recessive Five fingers Heterozygous Use a Punnett square to cross a normal parent with a heterozygous parent. What are their chances of having a child with polydactyly?

38. Early Ideas - Heredity Gregor Mendel was an Austrian monk who decided to run experiments on pea plants Gregor Mendel was an Austrian monk who decided to run experiments on pea plants –His data revealed patterns of inheritance –Father of genetics It was originally believed a child’s traits were the result of “blending” between parents’ traits It was originally believed a child’s traits were the result of “blending” between parents’ traits Nothing was known about Nothing was known about DNA! DNA!

39. Mendel’s Pea Plants Why did Mendel use pea plants? 1. Peas had several contrasting traits he could observe easily contrasting traits he could observe easily 2. He understood their method of their method of reproduction reproduction 3. They reproduced quickly 4. They can self- pollinate Characters investigated by Mendel

40. Reproduction in Plants Plant cells undergo meiosis, just like animals, to create plant gametes Plant cells undergo meiosis, just like animals, to create plant gametes –Plant sperm =pollen –Plant egg = ovule

41. Reproduction in Plants Pollination Pollination –Pollen released –Pollen fertilizes the ovules –Similar to fertilization in animals Mendel could control how plants were fertilized because he understood this process Mendel could control how plants were fertilized because he understood this process Pollination Animation Pollination Animation Pollination Animation Pollination Animation

42. pollen ovum (egg) nuclei combine cell cycle (with mitosis) embryo formed PLANT sperm ovum (egg) nuclei combine cell cycle (with mitosis) embryo formed ANIMAL 3

43. Mendel’s Experiments Mendel let certain pea plants mate, or cross Mendel let certain pea plants mate, or cross He controlled and documented each generations’ traits He controlled and documented each generations’ traits –Parental generation (P) “original” group mated –First filial generation(F1) offspring of the parental cross –Second filial generation (F2) offspring of crossing two F1 plants

44. Mendel’s Results Key to Mendel’s understanding was that he looked at the results of each trait individually (i.e. flower color) Key to Mendel’s understanding was that he looked at the results of each trait individually (i.e. flower color) Mendel realized that blending was NOT happening and there were characteristic patterns of inheritance Mendel realized that blending was NOT happening and there were characteristic patterns of inheritance

45. Mendel’s Conclusions Rule #1: Principle of Dominance- Rule #1: Principle of Dominance- one allele can dominate so trait coded by other allele hidden. –i.e. R dominates over r when both present –Because we know this, we represent the round allele with a capital R.

46. Mendel’s Conclusions Law of Segregation- when gametes form, the two copies of our genes are separated so each parent gives only one in their egg or sperm Law of Segregation- when gametes form, the two copies of our genes are separated so each parent gives only one in their egg or sperm This gave us the idea of meiosis and how gametes are formed! This gave us the idea of meiosis and how gametes are formed! Pea Parent 1: Pea Parent 2: Rr Rr Pea Parent 1: Pea Parent 2: Rr Rr R or r gametes meiosis

47. Mendels Conclusions Mendel saw pea plants with round peas and purple flowers, and pea plants with round peas and white flowers Mendel’s Law of Independent Assortment- inheritance of one trait will not affect inheritance of another Chromosomes and the genes on them most of the time are not “tied” together so we get a tremendous genetic mixture in a species! Everyone with brown hair does not have blue eyes Everyone who is left handed doesn’t have hairy feet

49. Rules of Genetics

50. Genetics Rules After Mendel Rule #1 Principle of Dominance Rule #1 Principle of Dominance Rule #2: Incomplete dominance -some alleles aren’t completely dominant so they BLEND Rule #2: Incomplete dominance -some alleles aren’t completely dominant so they BLEND Rule #3: Codominance -some alleles dominate together so BOTH ARE SEEN Rule #3: Codominance -some alleles dominate together so BOTH ARE SEEN Rule #4: Sex-linked genes -ALL alleles on a male’s X chromosome (X-linked) are expressed Rule #4: Sex-linked genes -ALL alleles on a male’s X chromosome (X-linked) are expressed

51. Complete Dominance Rule #1: Some alleles completely dominate over others: Rule #1: Some alleles completely dominate over others: –B= brown eyes –b=blue eyes –Bb= brown eyes, so B is completely dominant. –One allele capital, the other lower case

52. Incomplete Dominance Rule #2: Some alleles DON’T Rule #2: Some alleles DON’T COMPLETELY DOMINATE, so they blend: COMPLETELY DOMINATE, so they blend: –R= red flowers –r= white flowers –Rr = pink flowers –One allele capital, the other lower case PINK FLOWERS!!! BLENDING!!!

53. Codominance Rule #3: Some alleles dominate TOGETHER so they BOTH are shown Rule #3: Some alleles dominate TOGETHER so they BOTH are shown –H = brown hair on horses –H’ = white hair on horses –HH’ = both brown and white hairs, so the horse is roan color. –Blood types are like this, too.

54. Antigens-markers on cells  Antigens-markers on cells  Blood type determined by your markers on your red blood cells  4 blood group phenotypes:  Type A has A antigens  Type B has B antigens  Type AB has A and B antigens  Type O has no antigens Blood Types

55. Multiple Alleles  Multiple alleles- 3 different forms of the gene code for blood types I A, I B, and i –Allele I A codes for “A” antigen –I B codes for “B” antigen –i codes for none

56. Multiple Alleles 6 blood group genotypes 6 blood group genotypes Complete dominance- I A and I B dominate over i Complete dominance- I A and I B dominate over i Codominance- I A I B genotype shows BOTH A and B antigens Codominance- I A I B genotype shows BOTH A and B antigens Both alleles that codominate are written with capital letters! Both alleles that codominate are written with capital letters!

57. Antibodies Your body’s immune systems creates antibodies against anything foreign Your body’s immune systems creates antibodies against anything foreign –Antibodies-proteins produced by your immune system to fight off things that look “foreign”  Type A--makes anti-B antibodies  Type B--makes anti-A antibodies  Type AB--makes NO antibodies— universal receiver  Type O--makes anti-A and anti-B antibodies— universal donor

58. Sex-Linked Genes Rule #4: sex-linked genes: ALL alleles on a male’s X chromosome (X-linked) are expressed Rule #4: sex-linked genes: ALL alleles on a male’s X chromosome (X-linked) are expressed –Male sex chromosomes?_________ –Female sex chromosomes?_________ –We also call sex-linked genes by another name, X-linked, because the X chromosome has the majority of the genes

59. Sex-Linked Genes In males, EVERY gene on their X chromosome is expressed. The Y doesn’t have the same genes In males, EVERY gene on their X chromosome is expressed. The Y doesn’t have the same genes In females this is not the case because they have another copy on their other X chromosome to overcome it In females this is not the case because they have another copy on their other X chromosome to overcome it Genes: 1000 1000 1000 45

60. Sex-Linked Genes Examples of sex-linked disorders: Examples of sex-linked disorders: –Colorblindness –Hemophilia –Fragile X Syndrome –Duchene Muscular Dystrophy –Cleft Palate –Vitamin D Resistant Ricketts –3 types of deafness –Male Pattern Baldness X-linked recessive disorder

61. Who does a boy get his Y chromosome from? His X?

62. Sex-Linked Genes Genes that occur on sex chromosomes are written with X’s and Y’s to show this special situation. Genes that occur on sex chromosomes are written with X’s and Y’s to show this special situation. –I.e. red-green colorblindness is a recessive trait. It is found on the X chromosome, not the Y. –We write the alleles this way:  X C = colorblindness  X C = normal  The slash indicates it is a lower case letter so there is no confusion 4 Sex-Linked Traits: 1. Normal Color Vision: A: 29, B: 45, C: --, D: 26 2. Red-Green Color-Blind: A: 70, B: --, C: 5, D: -- 3. Red Color-blind: A: 70, B: --, C: 5, D: 6 4. Green Color-Blind: A: 70, B: --, C: 5, D: 2

63. Sex-Linked Genes Try to complete this table: Try to complete this table: PhenotypesGenotypes Normal Male Colorblind Male Normal Female Normal “carrier” Female Colorblind female

64. Sex-Linked Genes Try to complete this table: Try to complete this table: PhenotypesGenotypes Normal Male X C Y X C Y Colorblind Male X C Y X C Y Normal Female X C X C X C X C Normal “carrier” Female X C X C X C X C Colorblind female X C X C X C X C

66. Two Types of Mutations Either type of mutation can involve autosomes (chromosomes 1-22) or sex chromosomes (X & Y) Either type of mutation can involve autosomes (chromosomes 1-22) or sex chromosomes (X & Y) –Gene mutation- single gene’s nucleotide sequence affected, and therefore the protein it codes for is defective –Chromosomal mutation- missing or extra chromosome and ALL of its genes from incorrect chromosome split during meiosis

67. Gene Mutations This type of mutation determined by sequencing the DNA from a person’s cells This type of mutation determined by sequencing the DNA from a person’s cells –Insertion –Substitution –Deletion Insertion Deletion Substitution

68. Chromosomal Mutations This type of mutation is determined by creating a karyotype, or picture of chromosomes, from a person’s cell This type of mutation is determined by creating a karyotype, or picture of chromosomes, from a person’s cell –Monosomy—having one less chromosome (45) –Trisomy—having an extra chromosome (47) –Deletion—missing part of a chromosome –Nondisjunction

70. What is a Karyotype? Karyotype- picture of the chromosomes in a somatic cell Karyotype- picture of the chromosomes in a somatic cell 46 chromosomes in a normal, human karyotype 46 chromosomes in a normal, human karyotype

71. What can be determined from looking at a karyotype? 1.) Sex of the individual 1.) Sex of the individual –Sex chromosomes -either XX (female) or XY (male) –Autosomes-all chromosomes except sex chromosomes 2.) Chromosomal mutations 2.) Chromosomal mutations

72. What can be determined from looking at THIS karyotype?

73. A trisomy called Klinefelter’s Syndrome--male

74. Amniocentesis Method for obtaining fetal cells to check for defects Method for obtaining fetal cells to check for defects This is a risky procedure and should ONLY be performed on women who: This is a risky procedure and should ONLY be performed on women who: –Are in their mid 30’s or older –Have had a previous child with a chromosomal defect

75. Types of Genetic Disorders There are two types of disorders, depending on what DNA is affected There are two types of disorders, depending on what DNA is affected –Sex-linked disorders- caused by affected DNA of the sex chromosomes (the 23 rd pair…X or Y) –Autosomal disorders- caused by affected DNA of the autosomes (pairs 1-22)

76. Sex-Linked Disorders Sex-linked disorder – disease involving the sex chromosomes or a gene on them Sex-linked disorder – disease involving the sex chromosomes or a gene on them –Recessive gene on the X chromosome is more likely to be expressed in males because there is no second X –Alleles written as X A, X a or X B, X b etc.

78. Sex-Linked Disorders Sex-Linked Disorders 1- Color Blindness X-linked recessive disorder X-linked recessive disorder Gene mutation on X chromosome Gene mutation on X chromosome 1 of 10 males 1 of 10 males 2- Hemophilia X-linked recessive disorder X-linked recessive disorder Gene mutation on X chromosome. Gene mutation on X chromosome. 1 of 5,000 males 1 of 5,000 males Interfere with normal blood clotting Interfere with normal blood clotting ONLY THE SEX CHROMOSOMES ARE INVOLVED

79. Sex-Linked Disorders 3- Klinefelter Syndrome (XXY) 1 of 1,000 males. 1 of 1,000 males. Trisomy- extra X chromosome so chromosomal mutation Trisomy- extra X chromosome so chromosomal mutation

81. Sex-linked Disorders 4- Turner’s Syndrome (XO) 1 of 10,000 females 1 of 10,000 females Monosomy- one of X chromosomes is either missing or inactive so chromosomal mutation Monosomy- one of X chromosomes is either missing or inactive so chromosomal mutation Have immature female appearance and lack internal reproductive organs Have immature female appearance and lack internal reproductive organs

83. Autosomal Disorders Autosomal disorder - disease involving the 22 pairs of chromosomes that are NOT sex chromosomes (X,Y) and any genes on them Autosomal disorder - disease involving the 22 pairs of chromosomes that are NOT sex chromosomes (X,Y) and any genes on them Alleles written as A, a or B, b etc. Alleles written as A, a or B, b etc.

84. AaAa AaAaAaAa aaAaAaAA

85. Autosomal Disorders 1- Cystic Fibrosis Recessive disorder Recessive disorder Mutated gene on chromosome 17 Mutated gene on chromosome 17 Characterized by excessive, THICK secretion of the mucus in the body Characterized by excessive, THICK secretion of the mucus in the body

87. Autosomal Disorders 2- Huntington Disease Dominant disorder Dominant disorder Mutated gene on chromosome 4 is responsible. Mutated gene on chromosome 4 is responsible. Causes degeneration of neurons producing dementia, and random jerking movements Causes degeneration of neurons producing dementia, and random jerking movements

88. Autosomal Disorders 3- Phenylketonuria (PKU) Recessive disorder Recessive disorder Mutated gene on chromosome 12 Mutated gene on chromosome 12 Mental retardation can result due to lack of ability to breakdown phenylketones Mental retardation can result due to lack of ability to breakdown phenylketones 4- Sickle-Cell Anemia 1 of 12 U.S. African Americans 1 of 12 U.S. African Americans Recessive disorder Recessive disorder Mutated gene on chromosome 11 Mutated gene on chromosome 11 Blood clots Blood clots

89. Autosomal Disorders 5- Tay-sachs Disease Recessive disorder Recessive disorder European Jewish ancestry European Jewish ancestry Mutated gene on chromosome 15 Mutated gene on chromosome 15 Tay-sachs—One Wrong Letter Tay-sachs—One Wrong Letter

90. Autosomal Disorders 6- Down Syndrome 1 in 1,000 live births 1 in 1,000 live births Trisomy-extra Chromosome 21 so chromosomal mutation Trisomy-extra Chromosome 21 so chromosomal mutation Risk increases with mom’s age Risk increases with mom’s age Mild to severe mental retardation Mild to severe mental retardation

92. GENETIC DISORDERS Autosomal Disorders Chromosomes 1-22 Sex-Linked Disorders Sex Chromosomes X and Y Gene Mutations 1 gene mutated on chromosomes 1-22 Alleles: A, a or B, b, etc. Chromosomal Mutations Extra or missing chromosome 1-22 shown by karyotype Gene Mutations 1 gene mutated on X chromosome Alleles: X A, X a or X B, X b etc. Chromosomal Mutations Extra or missing sex chromosome shown by karyotype EXAMPLES?

93. How Do We Know About Our Genes? Human Genome Project Human Genome Project –Began in 1990; complete 2003 –Goals:  Determine complete sequence of the 3 billion DNA bases in human DNA  Identify all human genes for further biological study

94. The Unknown Gene number, exact locations and functions Gene number, exact locations and functions Gene regulation Gene regulation DNA sequence organization DNA sequence organization Chromosomal structure and organization Chromosomal structure and organization

95. Ethical, Legal and Social Issues Fears Fears –Genetic information used to harm or discriminate  Deny access to health insurance  Deny employment  Deny education  Deny loans?  Cloning? –DNA Databases DNA DatabasesDNA Databases

96. Cloning Cloning -creating many Cloning -creating many genetically identical cells from one cell Creation of genetically Creation of genetically identical organisms

97. Why Clone Animals? To answer questions of basic Biology Five genetically identical cloned pigs. For herd improvement. To satisfy our desires (i.e. pet cloning) For pharmaceutical production.

98. Is Animal Cloning Ethical? The first cloned horse and her surrogate mother/genetic twin. As with many important questions, the answer is beyond the scope of science.

99. Biotechnology Dolly and surrogate Mom Genetically modified rice. Embryonic stem cells and gene therapy Biotechnology Video