BIO 124 Lecture Notes - Lecture 4: Sexual Selection, Balancing Selection, Allele Frequency
4 Apr 2016
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Document Summary
Microevolution- change in allele frequency of a population. Gene variability- % of loci that are heterozygous. Nucleotide variability- measured on molecular level, usually occurs in noncoding regions. Only mutations in cells that produce gametes can be passed to. Point mutation- change in one base of a gene. Duplication of dna increases genome size, less harmful. Fixed allele- all individuals in a population are homozygous for the same allele. Gene pool- all alleles for a loci in a population. Genetic drift- how allele frequencies luctuate unpredictably between generations. Bottleneck efect- reduction in population size due to environmental change. Founder efect- individuals become isolated from larger population. Evolution by natural selection involves chance and sorting. Adaptive evolution- increase in the frequency of alleles that improve itness. Relative itness- contribution an individual makes to the gene pool of the next generation. Selection favors genotype by acting directly on phenotype. Stabilizing- intermediate variants & acts in extreme phenotypes.
