Mechanisms of Evolution

University:
Princeton University
Course:
BIO 121 | General Biology
Academic year:

2024
Views:

0

Pages:

2
Author:

christina lambrou

Mechanism of evolution When a population is in Hardy-Weinberg equilibrium for a gene, it is not evolving and allele frequencies will stay the same across generations. Five Basic Assumptions: no mutation, random mating, no gene flow, infinite population size and no selection. If the assumptions are not met for a gene the population may evolve, and it's not in HW equilibrium. HARDY-WEINBERG EQUATION: p^2 + 2pq + q^2 = 1 The factors that can modify the equilibrium of Hardy-Weinberg are: A. Mutations: RANDOM PROCESS Casual events changes in the genetic information, they can be beneficial, neutral, harmful. B. Non-random mating: Organisms may prefer to mate with others of the same genotype or of different genotypes. Non-random mating won't make allele frequencies change by itself though it can alter genotype frequencies. C. Gene Flow: Movement of genes into or out of a population (due to their movement or their eggs). They may have new alleles or the same in diff. proportions alternating the genetic equilibrium. Gene flow can be important for genetic variation. D. Non-infinite population size (genetic drift) RANDOM PROCESS Involves changes in allele frequency due to chance events while selecting alleles for the next generation. It can occur in any population of not infinite size but it has a stronger effect on small populations. E. Natural selection Occurs when one allele makes an organism more or less fit, able to survive and reproduce. Variation, differential reproduction, heredity = evolution by natural selection. Natural selection and artificial selection act on alleles.