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Non-Mendelian Inheritance

Non-Mendelian Inheritance

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Non-Mendelian Inheritance

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  1. Non-Mendelian Inheritance

  2. AaBbCc AaBbCc Sperm 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 1/8 Eggs 1/8 1/8 1/8 1/8 Phenotypes: 1/64 6/64 15/64 20/64 15/64 1/64 6/64 Number of dark-skin alleles: 2 6 0 3 4 5 1 Polygenetic Inheritance -a trait is controlled by more than two alleles. Each dominant allele has a quantitative effect Ex. Skin color

  3. Height in Human Beings

  4. Frequency Distributions inPolygenic Inheritance

  5. Sex Determination -out of 46 only 2 are sex chromosomes = X & Y -XX = female, XY = male -44 are autosomes- code for everything else

  6. Sex Linked Genes -Carried on only the X or Y chromosome -Ex: Color blindness is a recessive trait carried only on the X chromosome (XC or Xc). A female needs to be Xc Xc to get it, but a male only has to be Xc Y to get it. So more males are color blind. XC Xc XC Y

  7. Numbers That You Should See If You Are In One Of The FollowingFour Categories: [Some Letter Choices Show No Visible Numbers] 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

  8. Pedigree- a chart showing genetic inheritance

  9. Autosomal Recessive Pedigree Chart

  10. Autosomal Dominant Pedigree Chart

  11. Autosomal Recessive Disorders • Tay-Sachs Disease • Progressive deterioration of psychomotor functions. Lipid accumulation in brain cells. Death in childhood • Cystic Fibrosis • Mucus in bronchial tubes and pancreatic ducts is particularly thick and viscous • Phenylketonuria (PKU) • Lack enzyme for normal metabolism of phenylalanine. Mental retardation Albinism- lack of pigment (melanin) Sickle Cell (homozygous)

  12. Cystic Fibrosis Therapy

  13. Autosomal Dominant Disorders • Alzheimers (mental deterioration) • Achondroplasia (dwarfism) • Neurofibromatosis • Tan or dark spots develop on skin and darken • Small, benign tumors may arise from fibrous nerve coverings • Huntington Disease • Neurological disorder • Progressive degeneration of brain cells • Severe muscle spasms • Personality disorders

  14. A Victim of Huntington Disease

  15. Huntington Disease:Normal and Diseased Brain

  16. Incomplete Dominance the alleles are blended together to form an intermediate phenotype -    example:snap dragon color (red, white or pink)

  17. Co-Dominance - Both alleles are expressed in the phenotype (ex. Sickle cell anemia) BB= normal cell bb=sickle cell Bb Both (carrier)

  18. Phenotype (blood group) Red blood cell appearance Genotype Blood Type -Co-dominant: -caused by multiple alleles – 3 or more types A = has only A carbs. B = has only B carbs. AB = both AB carbs. O = no carbs. A B AB O

  19. Carbohydrate Allele Phenotype (blood group) Red blood cell appearance Genotype IA A B IB i none (a) The three alleles for the ABO blood groups and their associated carbohydrates Fig. 14-11 IAIA or IA i A B IBIB or IB i AB IAIB ii O (b) Blood group genotypes and phenotypes

  20. RH factor -Rhesus factor- antigens on the surface of blood cells that can cause an immune response • Positive (+) blood has antigens • Negative (-) blood has no antigens -a negative mother could harm a positive fetus. -a negative person getting positive blood can be harmed

  21. Epistasis  BbCc BbCc Sperm 1/4 1/4 1/4 1/4 BC bC Bc bc • One gene alters the expression of another gene Eggs 1/4 BC BBCc BBCC BbCC BbCc 1/4 bC bbCC bbCc BbCC BbCc 1/4 Bc BBcc Bbcc BBCc BbCc 1/4 bc BbCc bbCc Bbcc bbcc : 4 9 : 3

  22. Pleiotrophy • Some genes control more than one trait. (ex. Pea flower and seed color are controlled by one gene)

  23. Multifactorial genetics • Multifactorial traits are affected by genotype and the environment • Norm of reaction-phenotype range (more acid or aluminum results in darker flowers

  24. Himalayan Rabbits