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RE: Evolution 101 #2 - Genotype, Phenotype, Genes, Alleles and Population Genetics Model
Do you have some means to quantify how large are the deviations from the Hardy-Weinberg principle, in real life?
Do you have some means to quantify how large are the deviations from the Hardy-Weinberg principle, in real life?
Yes, and I will write in detail about this in the next post. Testing for deviations from Hardy-Weinberg proportions are usually made to check if there is a random mating present in populations with respect to a particular locus. If we know all the genotypes and allele types present in a population gene pool, we can easily calculate predicted, hypothetical (H-W) frequencies. After that, geneticists collect actual data and calculate observed, real frequencies of alleles and genotypes. The difference between predicted and observed frequencies is deviation from H-W. We know what events influence allele frequencies and in what way, so conclusion why the frequencies are changed can be made. For example, non-random mating increases frequency of the homozygous genotypes, which means that has an influence on genotype frequencies, however, it doesn't change allele frequencies. Unlike non-random mating, genetic drift ( sampling error from generation to generation, strong influence in small populations) will change the allele frequencies, which leads to deviations of H-W principle. All this with more math in the next post! :)
It was such a big step in undergrad, after learning the HW principle, to understand that it's a theory that only applies to a perfectly randomized allele in a population. I remember a lot of fellow students not getting this aspect of the principle and thinking it always explained the distribution of genotypes no matter what.
thanks for this already well detailed answer. I am looking forward to the next post (especially the math part which I like a lot) :)