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Unformatted text preview: Population genetics emerged as a branch of genetics in the 1920s and 30s. A population is a group of interbreeding individuals. Polymorphic genes (literally "manyformed") are commonly present as two monomorphic genes exist predominantly ( 99 % ) as a single allele. Singlenucleotide polymorphism (SNP) is the smallest type of genetic change that can occur within a single gene, and it is the most common change. (Here "polymorphism" means "difference in genes".) Allele frequency is # of genotype frequency is # of indiv. with that genotype/total pop. p q = 1, where p and q are allele frequencies. The HardyWeinberg equation states that, given random mating and infinite population size, for two parents and a gene that exists in two alleles, p q 2 = 1 = p 2 2 pq q 2 (think Punnett squares for a pop. with random mating, no sampling error, PP Pq Pq qq , where p is the frequency of allele p, q is the frequency of allele q, p 2 is the probability of producing a homozygous dominant indiv., 2pq is the prob. of a heterozygous individual, etc. The equation predicts an equilibrium dominant indiv....
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This note was uploaded on 04/14/2008 for the course BIOL 115 taught by Professor Diggs during the Fall '07 term at Austin College.
 Fall '07
 Diggs
 Genetics, Population Genetics

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