Albinism

1. Albinism • Caused by altered genes, resulting in the absence of the skin pigment melanin in hair and eyes • White hair • Very pale skin • Blue Eyes • Pink pupils

2. Albinism • Impaired Vision • It is vital that people with albinism use sunscreen when exposed to sunlight to prevent premature skin aging or skin cancer • High risk of skin cancer

3. Tay-Sachs Disease • Caused by the absence of the enzymes (in lysosomes) responsible for breaking down fatty acids called gangliosides • Gangliosides accumulate in the brain, inflating brain nerve cells and causing mental deterioration

4. Tay Sachs Disease • Children with Tay-Sachs, a progressive neurodegenerative disease that attacks nerve cells, usually die before age 5. • Children will go deaf, have seizures, and, ultimately, become unable to swallow or breathe.

5. Galactosemia • Recessive genetic disorder characterized by the inability of the body to digest galactose. • Lactose = Galactose + Glucose • Symptoms: • • liver damage or failure• cataracts• brain damage• infection

6. Galactosemia • Treatment requires the strict exclusion of lactose/galactose from the diet.

9. Dominant Genetic Disorders • Dominant Gene results in disorder: • Huntington’s Disease • Achondroplasia

10. Achondroplasia • is a genetic condition that causes small body size and limbs that are comparatively short. • Obesity • Breathing problems (apnea) • Recurrent ear infections (otitis media). • Other health problems

11. Huntington’s Disease • affects the nervous system. • Huntington's disease is a progressive, degenerative disease that causes certain nerve cells in your brain to waste away. • As a result, you may experience uncontrolled movements, emotional disturbances and mental deterioration.

12. Huntington’s Disease • Diminished memory, immediate and short-term (long-term memory usually remains intact) • Disease usually manifests itself by age 35

14. Do Now • Peter and Lois decide to try for a 4th child. • Determine the possible genotype and phenotype ratios of the following cross: • DdEe X ddEe • D= Brown hair • d=red hair • E=fluffy hair • e=thinning hair

15. Pedigree • Shows history of a trait in a family • Allows researchers to analyze traits within a family

16. Symbols for Pedigree

17. Using Pedigrees • Inferring Genotypes • Knowing physical traits can determine what genes an individual is most likely to have. • Predicting Disorders • Scientists use pedigree analysis to study: • inheritance patterns • determine phenotypes • genotypes.

18. Sample Pedigree

19. Think – Pair - Share

20. Dominant or Recessive Trait?

21. Dominant or Recessive Trait?

22. Do Now • Fill in the genotypes for the following pedigree • B=brown eyes • b = blue eyes

23. Test Cross • When the genotype of an individual is unknown, cross the individual with a homozygous recessive • The outcome of the cross determine the genotype of the unknown

26. Do Now • Fill in the pedigree for Achondroplasia. Use the variable A.

27. 11.2 Incomplete Dominance: • Heterozygous phenotype is an intermediate phenotype between the two homozygous phenotypes. • Two alleles are blended • Ex) Four O’clock Flowers • Red + White = Pink

28. Codominance • Neither trait is dominant instead, both traits are shown (No Blending) • Ex) Roan Cows • Red + White = REDANDWHITE

29. Sickle Cell Disease • Affects red blood cells and ability to transport oxygen. • Homozygous recessive alleles= • Heterozygous= • Homozygous dominant alleles=

30. Sickle Cell and Malaria • People who are heterozygous for sickle cell, have a higher resistance to malaria.

33. Multiple Alleles • Traits determined by more than 2 alleles Ex. Blood Typing (3 alleles ABO) • A and B are dominant to O

34. Do Now • A parent with the blood type A and one with B have a child with type O blood. What are the parents genotypes? • Draw out the punnett square.

35. Universal Donor

36. Sample Problem • Determine the possible offspring of the following crosses • 1. AB and O • 2. AA and BO • 3. AB and AB

37. Coat Color of Rabbits • Rabbits have a hierarchy of coat color • 4 alleles (C, cch, ch,and c) • Dominant C > cch> ch > c Recessive • C Full color • cch Chinchilla • ch Himalayan • c albino

38. Complex Inheritance and Human Heredity Coat Color of Rabbits Chinchilla Albino Full Color Himalayan

39. Let’s try a sample problem • cc x Ccch • Genotype and phenotype ratios

40. What do you see?

41. What do you see?

42. Sex Linked Traits • Traits located on the sex chromosomes (X or Y) • X linked: gene is located on the X chromosomes • Y linked: gene is located on the Y chromosome

43. What are the chances of having a girl? • How would you go about solving it?

44. Sex-Linked Traits • A man who is color blind marries a woman that is heterozygous for color blindness. What is the chance of having a color blind boy?

45. Do Now • A man that is color blind marries a woman that is a carrier for the disorder. What is the chance of having a color blind girl?

46. Hemophilia • Sex linked disorder characterized by delayed blood clotting • Located on the X Chromosome • Seen in the Royal Family of England

47. Hemophilia

48. Complex Inheritance and Human Heredity Chapter 11 Polygenic Traits • Polygenic traits arise from the interaction of multiple pairs of genes.

49. Polygenic Inheritance P Generation AABBCC (very dark) aabbcc (very light) F1 Generation • Skin Pigment AaBbCc AaBbCc F2 Generation Sperm Eggs Figure 9.22

50. What is the difference between polygenetic and multiple alleles?