ATH 351-01

evolutionary genetics:genes and human evolution

Mendelian genetics (Gregor Mendel, 1822-1884)

  • Austrian monk
    • pea breeding experiments
    • discovered laws of inheritance
      • transmission of physical traits
      • source of new traits
      • biostatistics
  • laws of inheritance
    • particulate inheritance
      • factors=genes
    • law of segregation (genetic recombination)
    • law of independent assortment

law of segregation

  • dominance & recessiveness
  • genotype & phenotype
  • homozygous & heterozygous genotypes: number of generations
    1. yy + YY
    2. Yy + Yy
    3. 1yy + 2Yy + 1YY

example: Fast & Bully Whippets

genes & evolution

  • independent evidence for evolution
    • DNA code shared by all organisms (ATCG)
    • ATG = universal start code for protein
  • structural & regulatory genes
  • Mendelian traits
    • ABO blood type, lactose intolerance, cystic fibrosis
    • pleiotropy = multiple effects of one pair of genes
  • polygenic traits
    • skin color, eye color, stature, body mass
  • mutation
    • change in genetic code
      • new, different trait
    • mutagens
    • chromosomal crossover
  • new synthesis
    • both mutation & natural selection

modern genetics

  • two kinds of natural selection
    • directional selection
    • stabilizing selection
  • human genome project
    • mapping human genes
    • species comparison

biochemical genetics chart

genes in populations

  • gene pool & collective phenotype
  • gene frequency change = evolution
  • gene flow
  • genetic drift
    • founder effect
  • genetic load

gene flow: 2 separate populations combine, new population has allele frequencies unlike either original population

gene drift: original population splits off, founded populations have separate frequencies (fission/founder effect)

summary

  • increasing genetic variation
    • recombination
    • crossing over
    • mutation
    • gene flow
  • reducing genetic variation
    • natural selection
    • gene drift
Advertisements
Both comments and trackbacks are currently closed.