23_Biol221_04_14_2-11

Nonsexual reproduclon aa aa aa aa

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Unformatted text preview: d 1 ­q = p, then p2 +2pq +q2 =1 where p and q are allele (or marker) frequencies in the populaLon 27 Requirements for Hardy Weinberg Equilibrium 1. Organisms reproduce sexually. 2. MaLng is random. 3. PopulaLon size is very large. 4. MigraLon in or out is negligible. 5. MutaLon does not occur. 6. SelecLon does not act on the alleles under consideraLon. 28 Hardy Weinberg EquaLon If 1 ­p = q and 1 ­q = p, then p2 +2pq +q2 =1 where p and q are allele (or marker) frequencies in the populaLon 29 Sexual ReproducLon and VariaLon 30 Sexual ReproducLon and VariaLon M/M = p2= (.913) • (.913) = 83% 31 Sexual ReproducLon and VariaLon N/N = q2= (.087)• (.087) = 0.8% 32 Sexual ReproducLon and VariaLon M/N = 2pq= (.913) • (.087) •(2) = 16% 33 Sexual ReproducLon and VariaLon .835 + ½ (.156) = p = .913 34 What is the frequency of A and a? hHp://www.nature.com/scitable/topicpage/the ­variety ­of ­genes ­in ­the ­gene ­6526291 Requirements for Hardy Weinberg Equilibrium 1. Organisms reproduce sexually. 2. MaLng is random. 3. PopulaLon size is very large. 4. MigraLon in or out is negligible. 5. MutaLon does not occur. 6. SelecLon does not act on the alleles under consideraLon. 36 Requirements for Hardy Weinberg Equilibrium 1. Organisms reproduce sexually. • Non ­sexual reproducLon AA AA A/a A/a a/a a/a 37 Requirements for Hardy Weinberg Equilibrium 2. Ma=ng is random. Inbreeding (and posi=ve assorta=ve ma=ng): maLng by related individuals will increase the numbers of homozygous individuals in the populaLon. 38 Requirements for Hardy Weinberg Equilibrium 2. Ma=ng is random. Self ­IncompaLbility: Some plants have mechanism that prevent their own pollen or related pollen from ferLlizing their eggs. This mechanism promotes out ­crossing. 39 Requirements for Hardy Weinberg Equilibrium 2. Ma=ng is random. • The frequency of AA maLng with AA should equal (p2)(p2) • A/a with A/A should equal (2pq)(p2) • a/a with a/a should equal (q2)(q2) • A/a with a/a should equal (2pq)(q2) 40 Requirements for Hardy Weinberg Equilibrium 3. Popula=on size is very large. Small populaLons are suscepLble to geneLc drid and founder effects GeneLc drid: When the beetles reproduced, just by random luck more brown genes than green genes ended up in the offspring. In the diagram at right, brown genes occur slightly more frequently in the offspring (29%) than in the parent generaLon (25%). 41 hHp://darwin.eeb.uconn.edu/simulaLons/jdk1.0/drid.html 43 Requirements for Hardy W...
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