Ecology 3

  1. QG
    quantitative genetics - the scientific study of the statistical analysis of the effects that heredity and environment have on phenotypic variation
  2. 2 ways to measure Darwin's step 4
    • selection differential (s)
    • selection gradient (B) "beta"
  3. selection differential (s)
    • -describes the strength of selection relative to the distribution or variance of the phenotypic trait
    • -difference in mean phenotype between the population as a whole and the selected parents of the next generation
  4. heritability
    the proportion of phenotypic variation in a population that is attributable to genetic variation among individuals
  5. selection gradient (B) "beta"
    • the regression slope of "fitness" estimate on phenotype
    • used more in ecological studies because it's easier to measure in the field
  6. selection response (R)
    the change in mean phenotype between parental generation before selection, and offspring generation (before selection on it, after selection on parental generation)
  7. The breeder's equation
    • R = h2 S
    • R = VA B"beta"
  8. VA
    • additive genetic variance
    • passed on from parents to offspring, as sum of 2 alleles effects, one from mom, one from dad
  9. VP
    • total phenotypic variance
    • S2 phenotypes
    • VP = VG + VE
  10. narrow sense heritability
    • h2 = VA / VP
    • h2 = 0,1, or inbetween, if so R<S
  11. variance (V)
    • measure of dispersion about a mean or average
    • the standard deviation squared
  12. VG
    • genetic variance
    • VG = VA (additive) + VD (dominance - interation between alleles within a gene) + Vi (interaction among genes, gene networks)
    • **selection only responds to VA
  13. Vi
    • epistasis
    • interaction among genes, gene networks
  14. Ve
    environmental variance
  15. broad sense heritability
    • H2 = VG / VP
    • reflects all possible genetic contributions
  16. locus (plural loci)
    the specific location of a gene or DNA sequence on a chromosome
Card Set
Ecology 3
Day 3