BIOL 2200 Lecture Notes - Lecture 4: Allele Frequency, Panmixia, Gene Pool
25 Jan 2017
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Natural selection: traits vary among individuals within a population and may be heritable. Mendel in pea-shell: observed 3:1 patterns of inheritance of phenotypic traits, two alleles at a locus, dominant: determines phenotype, recessive: masked in phenotype, exceptions: incomplete or codominance, dominant does not equal adaptive. Me(cid:374)dels" exeperi(cid:373)e(cid:374)ts: bred pure bred purple flower with pure bred white flower, led to f1 offpsring that were all heterozygous, f2 generation 3:1 ratio purple:white flowers. If alleles transmitted by meiosis and random mating, frequencies do not change over time. Frequencies of alleles a1 and a2 given by p and q. Genotypic frequencies: a1a1 both donate a1 into gene pool, a2a2 both donate a2 into gene pool, a1a2 half donate a1 and other half give a2. To calculate allele frequencies: p= 0. 49 + (0. 42) = 0. 7, q= (0. 42) + 0. 09 = 0. 3, situation where population is in hardy wienburg equilibrium.
