AGB 121: Principles of Animal Genetics and Population Genetics (2+1)

FACTORS AFFECTING GENETIC CONSTITUTION

Factors affecting genetic constitution of a population

• Selection
  • Variation in fitness and heritability favors a single phenotype and therefore allele frequency continuously shifts in one direction
• Mutation
  • Change in DNA of genes and thereby introduce new allele are introduced into the gene pool
• Migration
  • Migration means movement of individuals
  • This movement introduces new alleles into the population (gene flow).
  • The gene frequencies in the population may be changed by immigration of individuals from another population or emigration of individuals from the population.
  • Dispersal of animals, pollen on the wind etc.
• Recombination
  • Exchange of gene segments shuffle the genes into new combinations which can result in organisms exhibiting different traits.
• Mating system 
  • Mating system two types: Random mating (Panmixia) and Non-random mating.
  • Individuals those are more closely (inbreeding) or less closely related mate more often rather than by chance.
  • Resulting in c hange of genetic constitution of a population.
• Random Genetic Drift
  • If populations are small enough, by chance, sampling will result in a different allele frequency from one generation to the next.
• Differences in fertility and viability
  • The individuals in a population (different genotypes) differ in fertility and contribute unequally to the next generation thus changing the gene frequency in the subsequent generation.