The Hardy-Weinberg principle (HWP) illustrates how genetic equilibrium is maintained between alleles and genotypes in a specific population. To achieve this hypothesis, there is the need to make multiple assumptions, which include the existence of large populations, lack of genetic mutation, lack of gene flow because of allele’s immigration or emigration, absence of natural selection and random mating. As a result, the allele frequency would be unaltered while the genotype frequencies attain equilibrium.
Thus, in a single generation, random mating achieves equilibrium. This implies that HWP, just like a Punnett square, can be used to determine the probability of offspring’s genotypes from those of their parents (Winter, 1998). Similarly, the frequency of a particular allele can be determined based on the prevalence of the dominant and recessive alleles. This is enabled by the fact that allele frequency can be assigned probabilistic values where its sum results in a unit.
An example on how to demonstrate the application of HWP to a population would involve the analysis of the mating selection. In this regard, the course of evolution in populations is altered. For randomly mating populations, individuals have equal chances of mating with individuals possessing different genotype types. In a non-random mating population, there exist higher chances of inbreeding or assortative mating (Jorjani, 1995).
Assortative mating refers to the chance of individuals with similar phenotypes mating due similar ancestry. Therefore, it influences the course of evolution, which violates the HWP equilibrium. Assortative mating outcome is the change in the frequency of allele and genotypes of a population.
Assortative mating leads to a high likelihood of similar genotypes breeding with other individuals of a similar genotype. As a result, this will lead to a rise in homozygosis. This is influenced by the disequilibrium in the genetic phase.
Consequently, the gametes will be similar through the rise in homozygote’s gametic frequency. Secondly, assortative mating increase the general population distinction due to similar genotypes exhibited by individuals retained under their line of ancestry. This can be illustrated by the fact that homozygote of the overall population would be widening due to the variation in the group. In this regard, the assortative mating influences the course of evolution leading to HWP interference.
Many factors contributed by the assortative mating influence the HWP. These factors include the number of genes responsible for the formation of phenotypes and the extent of assortative mating. With regards to the number of genes responsible for the creation of gametes, it influences the trait that will be exhibited by the individuals in the population.
For the extent of assortative mating, the degree of variation will be enhanced and the variation in phenotypes in the whole population will increase. This is mainly influenced by the fact assortative mating limits the ability of homozygote to vary at each individual gene (Davies, 1985).
In the plant and animal kingdom, the assortative mating plays a crucial role in interfering with the HWP. In the animal kingdom, an individual could be used to illustrate the variation that assortative mating contributes in HWP influencing the course of evolution. For individuals with certain genes, for example, dominant A and recessive a, the mating of the individual with an individual with similar genes would definitely result in an offspring with similar genes.
Over a long period, this would lead to the variation of the individuals in the whole population. On the other hand, in the plant kingdom, the breeding of flowers with red flowers continuously without the chance to breed with other colors would result in a variation that becomes severe over time in the whole population.
References
Davies, J. C. (1985). Body size in adult lesser snow geese assortative mating, heritability and fitness. Ottawa: National Library of Canada.
Jorjani, H. (1995). Assortative mating and selection in populations of various sizes: a review of the literature. Uppsala: Swedish University of Agricultural Sciences, Dept. of Animal Breeding and Genetics.
Winter, P. C., Hickey, G. I., & Fletcher, H. L. (1998). Instant notes in genetics. Oxford: Bios Scientific Publishers.