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Albinism

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. Albinism. Impaired Vision

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Albinism

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  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.

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

  8. 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

  9. 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.

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

  11. 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

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

  13. Symbols for Pedigree

  14. 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.

  15. Sample Pedigree

  16. Think – Pair - Share

  17. Dominant or Recessive Trait?

  18. Dominant or Recessive Trait?

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

  20. 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

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

  22. 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

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

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

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

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

  27. 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.

  28. Universal Donor

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

  30. 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

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

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

  33. What do you see?

  34. What do you see?

  35. 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

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

  37. 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?

  38. 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?

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

  40. Hemophilia

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

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

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

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