Provide 3 factors that can alter the proportion of homozygotes and heterozygotes from the predicted Hardy-Wein?
- Anonymous8 years agoFavorite Answer
Most populations do in fact conform to equilibrium when it is measured. The most common reasons that you find for deviations are:
1. Substructure within a population, which is by far the most common cause. You sample what you think is a single population and find that you have a heterozygote deficit. This is because the population actually consists of lots of smaller subpopulations which are not mixing.
2. Non-random mating, is also a common reason, where some individuals contribute more alleles to the next generation than others and therefore equilibrium is lost.
3. Selection at a locus will affect equilibrium for that gene only, but if you remove it from your measurements you often find that for all other loci equilibrium is maintained.
4. Genetic drift - common in small populations, where by chance certain alleles get driven to high frequency or fixed in the population, while others are randomly lost. This usually reduces heterozygosity.
- StarkLv 68 years ago
The Hardy-Weinberg equilibrium is a principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors. When mating is random in a large population with no disruptive circumstances, the law predicts that both genotype and allele frequencies will remain constant because they are in equilibrium.
The Hardy-Weinberg equilibrium can be disturbed by a number of forces, including mutations, natural selection, nonrandom mating, genetic drift, and gene flow. For instance, mutations disrupt the equilibrium of allele frequencies by introducing new alleles into a population. Similarly, natural selection and nonrandom mating disrupt the Hardy-Weinberg equilibrium because they result in changes in gene frequencies. This occurs because certain alleles help or harm the reproductive success of the organisms that carry them. Another factor that can upset this equilibrium is genetic drift, which occurs when allele frequencies grow higher or lower by chance and typically takes place in small populations. Gene flow, which occurs when breeding between two populations transfers new alleles into a population, can also alter the Hardy-Weinberg equilibrium.
Because all of these disruptive forces commonly occur in nature, the Hardy-Weinberg equilibrium rarely applies in reality. Therefore, the Hardy-Weinberg equilibrium describes an idealized state, and genetic variations in nature can be measured as changes from this equilibrium state.