Genetics

1. Genetics Chapter 10.2, 10.3, 11.1, and 11.2

2. Do Now- True for False if false, correct the statement. • 1. Certain acquired characteristics, such as mechanical or mathematical skill may be inherited. • 2. Certain thoughts or experiences of a mother mark or alter the hereditary makeup of an unborn child. • 3. Color blindness is more common in males than in females. • 4. A person may transmit characteristics to offspring which he/she does not show. • 5. Certain inherited traits may be altered by the stars, planets or moon early in development. • 6. The total number of male births exceeds female births each year.

3. The Problem…. • Born October of 2006: • These two boys are related… They are twins. • http://www.msnbc.msn.com/id/15447465/

4. Another Example…

5. How Can this be? Let’s Brainstorm.

6. Goal of this chapter on Genetics:

7. 1866 Gregor Mendel • “Father of Genetics” • Austrian Monk that studied pea plants • Pure breeds • Self Fertilization • Statistician who wanted to be a teacher • Discovered how traits were inherited in a population

9. How Genetics Began • The passing of traits to the next generation - inheritance or heredity. • Mendel performed cross-pollination in pea plants. • Mendel followed various traits in the pea plants he bred.

10. 7 Traits Mendel Studied

11. Mendel studied seven different traits. • Seed or pea color • Flower color • Seed pod color • Seed shape or texture • Seed pod shape • Stem length • Flower position

12. Mendel’s Crosses • P Generation: • F1 Generation: • F2 Generation:

13. Generations • P Generation • Parents • Pure – • F1 Generation • Hybrid – 2 different types of genes for a trait • F2 Generation • 3:1–Yellow : Green

14. Animation

15. r R Definitions • Genetics: • Study of hereditary • Gene: • Strand of DNA that codes for a protein (Trait) • Allele: • A version of a gene

16. r R Phenotype vs. Genotype • Phenotype: • Physical characteristics (What the individual looks like) • Ex) Red Petals • Genotype: • Alleles Received (genes you have) • Ex) RR

17. Homozygous and Heterozygous • Homozygous: • Having two of the same alleles for a particular trait • Ex. • Heterozygous: • Having two different alleles for a particular trait • Ex.

18. Dominant Vs. Recessive • Dominant hides the recessive trait in the heterozygousgenotype.

19. Think – Pair - Share • If Fred Flintstone is heterozygous for black hair. • (B=Black, b=blonde) • What is Fred’s genotype? • What is Fred’s phenotype? • Tweety bird is yy. (Y= yellow feathers, y=brown feathers) • 1. What is his genotype? • 2. What is his phenotype? • 3. Is he heterozygous or homozygous? Explain.

20. Do Now • Provide an example of the following terms: • Heterozygous • Homozygous • Genotype • Phenotype • Dominant • Recessive • Allele • Gene

21. W w Sperm Mendels 3 Laws • 1. Law of Segregation • Each allele a person has separates into different gametes • Ex. Ww – one W goes in one sperm and the other w goes into another sperm w W

22. Mendels 3 Laws • 2. Law of Independent Assortment • Gene pairs (homologous) will separate randomly into gametes

23. Mendels 3 Laws • 3. Law of Dominance • Traits exist in two possible forms (dominant and recessive) • The dominant forms hides the recessive trait in the heterozygous condition

24. R r R r Monohybrid Cross • R= Can roll your tongue • r= Can’t roll your tongue • Genotype Ratio: • Phenotype Ratio:

25. Genotypic vs. Phenotypic Ratios • Phenotype Ratio: • Ratio of different physical traits • Ex) Brown eyes ¼ or 25% • Genotype Ratio: • Ratio of the different possible alleles • Ex) Tt = ¼ or 25%

29. Sample Problems • Daffy Duck is heterozygous for black feathers. Daisy Duck is homozygous for yellow feathers. Set up a punnett square and determine probabilities of their potential offspring. (Both genotype and phenotype ratios!) • B = Black b = yellow

30. Do Now • Sponge Bob Square pants is heterozygous for brown eyes. Sandy is also heterozygous for brown eyes. Create a punnett square to determine the possible outcomes of their children.

31. Do Now • Sleeping Beauty has freckles. Her prince charming is heterozygous for no freckles. What are the chances of her children having freckles? Please show your work.

32. Setting up Dihybrid Crosses • 1. Determine parent genotypes • 2. Determine alleles to be passed down • 3. Set up punnet square • 4. Determine outcome • Phenotype Ratio • Genotype Ratio

33. Dihybrid Crosses • Looking at two different traits • Ex. Hair color and eye color • B=brown eyes • b=blue eyes • R=Brown hair • r=blonde hair • Mother is heterozygous for both traits • Father is heterozygous for eye color and homozygous dominant for hair color

35. The problem • Aladdin and Jasmine want to have children. Jasmine is homozygous dominant for black hair and black eyes. Aladdin is homozygous recessive for brown eyes and brown hair. B=black hair b=brown hair E=black eyes e=brown eyes

36. B=black hair b=brown hair E=black eyes e=brown eyes • Jasmine’s daughter falls in love with a man who is also heterozygous for hair and eye color. Determine possible genotype and phenotype ratios.

37. Do Now • BbTt X BBTt

38. Do Now • Mickey Mouse is heterozygous for Round ears and homozygous for Black eyes. Minnie Mouse also is homozygous for Floppy ears and heterozygous for Black eyes. Determine genotype and phenotype ratios. (B=black, b=brown, R=round, r= floppy.)

39. Do Now • Two dogs have puppies! The male dog is homozygous brown fur and heterozygous floppy ears. The female dog is heterozygous for brown fur and homozygous for straight ears. • B=brown fur b=blonde fur • F=Floppy ears f= straight ears • What ratio of the dogs would have brown fur and floppy ears?

40. Math Method • For a cross between TtBb and TtBB. • Do each cross individually and multiply the results together. • For TtBb

41. Quiz next class on 10.2 • QUIZ ON MONDAY ON: • Vocabulary words • Mendel • Mendel’s experiments • Monohybrid crosses ONLY

42. 10.3 Gene Linkage and Polyploidy • Several genes on a chromosome • Gene Linkage: • When two genes are close to each other on the same chromosome

43. Gene Linkage • Linked genes on a chromosome results in an exception to Mendel’s law of independent assortment • Linked genes usually do not segregate independently

44. Drosophila (Fruit Flies) • First organism with linked genes • Linked genes typically travel together during crossing over

45. Chromosome Map • Crossing over occurs more frequently between genes that are far apart • Map of genes on a chromosomes and frequency of crossing over

46. Polyploidy • Occurrence of one or more extrasets of all chromosomes in an organism. • Ex. A triploid organism (3n) - means that it has three complete sets of chromosomes.

47. True or False – Correct false statements _______   1. Crossing over occurs more frequently between genes that are close together on a chromosome. _______   2. Gene linkage was first studied by using garden peas. _______   3. Scientists call a drawing like the one shown below a chromosome map. _______   4. Chromosome map percentages represent actual chromosome distances.

48. Matching

49. 11.1 Basic Pattern of Human Inheritance • Recessive Genetic Disorders • Cystic Fibrosis • Albinism • Tay Sachs Disease • Galactosemia

50. Cystic Fibrosis • Affects the mucus-producing glands, digestive enzymes, and sweat glands • Chloride ions are not absorbed into the cells of a person with cystic fibrosis but are excreted in the sweat. • Without sufficient chloride ions in the cells, a thick mucus is secreted.