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Population Genetic3 - likely to land on heads almost...

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Population Genetics The Hardy-Weinberg Law As stated in the introduction to population genetics , the Hardy-Weinberg Law states that under the following conditions both phenotypic and allelic frequencies remain constant from generation to generation in sexually reproducing populations, a condition known as Hardy- Weinberg equilibrium. 1. large population size 2. no mutation 3. no immigration or emigration 4. random mating 5. random reproductive success This section will look in detail at the five conditions upon which the Hardy- Weinberg Law is contingent. Large Population A population must be large enough that chance occurrences cannot significantly change allelic frequencies significantly. To better understand this point, consider the random flipping of a fair coin. The coin is as likely to land on heads as it is on tails. If a coin is flipped 1000 times, it is
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Unformatted text preview: likely to land on heads almost exactly 50% of the time. However, as you may know from experience, if the same coin is flipped only ten times, it is much less likely that it will land on heads 5 times. The same holds true for allele distributions in populations. Large populations are unlikely to be affected by chance changes in allele frequencies because those chance changes are very small in relation to the total number of allele copies. But in small populations with fewer copies of alleles, chance can greatly alter allele frequencies. In small populations, a change in allelic frequencies and phenotypes based on random occurrences is called genetic drift....
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