BIOL 2905 Chapter Notes - Chapter 6.2: Allele, Allele Frequency, Founder Effect
22 Oct 2017
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Mutatio(cid:374)s (cid:272)a(cid:374) (cid:271)e deleterious (alter a(cid:374) i(cid:374)dividual"s stru(cid:272)ture fu(cid:374)(cid:272)tio(cid:374) or (cid:271)ehaviour i(cid:374) har(cid:373)ful ways) or advantageous (confers some benefit on an individual that carries it) or neutral (are neither harmful nor helpful. ) In diploid or polyploid species: gene flow: occurs when individuals leave one population, join another, and breed. Allele frequencies may change when gene flow occurs, because arriving individuals introduce alleles to their new population and departing individuals remove alleles from their old population. Tends to increase similarity in the two populations. If gene flow continues and no selection occurs, allele frequencies will eventually be identical. Gene flow is random with respect to fitness- the arrival or departure of alleles can increase or decrease average fitness depending on the situation. Migrating individuals must contribute to the next generation and gene pool in the new population. Gene flow can slow adaptation to local conditions. Emigration: movement out of a population: genetic drift: causes allele frequencies to change randomly.
