Genetics classic-genetics-mendelian-genetics2320


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Genetics classic-genetics-mendelian-genetics2320

  1. 1. Genetics  Classic Genetics – Mendelian Genetics  Principal of genetics 1. Dominance 2. The principal of independent assortment 3. The principal of segregation  Examples: color of flowers – red V.S. white dominant trait V.S. recessive trait complete dominance V.S. incomplete dominance genotype V.S. phenotype homozygous V.S. heterozygous monohybrid V.S. dihybrid gametes and zygotes Punnett square
  2. 2. Gregor Mendel Reference:
  3. 3. Crosses With Two Traits Smooth seeds (S) are dominant over wrinkled (s) seeds. Yellow seed color (Y) is dominant over green (y).
  4. 4. Human Genetics  Single trait genetic inheritance – blood type A B O  Blood type A, B are dominant versus O.  A and B are co-dominant. Blood type Phenotype Genotype Antigen Antibody A A AA, AO A B B B BB, BO B A AB AB AB AB -- Universal recipient O O OO -- AB Universal donor
  5. 5. Human Genetics – Cont’d Two traits genetic inheritance – TONGUE ROLLING (T)TONGUE ROLLING (T) V.S. non-rolling (t)non-rolling (t) WIDOW’S PEAK (W)WIDOW’S PEAK (W) V.S. straight hairline (w)straight hairline (w) Parents (P): TTWW x ttww gametes: TW tw F1 TtWw Heterozygous cross: TtWw x TtWw gametes: TW Tw tW tw TW Tw tW tw F2 ?
  6. 6. Punnett square – dihybrid cross Phenotype ratio --- 9:3:3:1   TW Tw tW tw TW TTWW TTWw TtWW TtWw Tw TTWw TTww TtWw Ttww tW TtWW TtWw ttWW ttWw tw TtWw Ttww ttWw ttww
  7. 7. Human chromosomes  All but one pair of chromosomes are the same in both males and females. They are designated autosomes. The remaining pair of chromosomes are sex chromosomes.  Human cells have a diploid chromosome number of 46. The nucleus contains 22 pairs of autosomes and 1 pair of sex chromosomes (X and Y).  Each chromosome in this karyotype is duplicated and so consists of two sister chromatids.
  8. 8. Male Karyotype Female Karyotype
  9. 9. Or Sex Chromosomes XY Male XX Female Karyotype The photos of chromosomes are arranged in order of size and numbered. Chromosomes 23 are the sex chromosomes.
  10. 10. Genetic Diseases 1. Tay – Sachs Disease 2. Maple Syrup Urine Disease (MSUD) 3. Chemochromatosis 4. Cystic Fibrosis 5. Colon Cancer 6. Breast Cancer 7. Alzheimer’s Disease 8. Hemophilia 9. Muscular Dystrophy 10. Sickle Cell Anemia 11. Fragile X Syndrome 12. Turner Syndrome 13. Down Syndrome 14. Klinefelter Syndrome 15. XXY condition 16. Color Blindness
  11. 11. Sex Linkage  Morgan – the color of eyes in fruit fly.  The sex linkage traits are usually on the X chromosome.  Sex-linked diseases: 1. Color Blindness 2. Duplchenne Muscular Dystrophy 3. Hemophilia  Color blindness genetic inheritance  Muscular dystrophy genetic inheritance
  12. 12. Abnormal Number of Chromosomes  Eduwards Syndrome (Trisomy 18)  Down’s Syndrome (Trisomy 21)  Pata Syndrome (Trisomy 13)  Turner Sundrome (Monosomy X)  Klinefelter Syndrome (XXY)  Crime Syndrome (XYY)
  13. 13. Trisomy 18 * Triploid Set of Chromosomes