Mutation
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Mutations could lead to occurrence of new alleles and thereby it changes the gene pool of the population.
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It may be favourable or deleterious to the individual’s ability to survive.
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If changes are advantageous, then the new alleles will tend to prevail by being selected in the population.
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If a wild allele A 1 mutates to A2 with a frequency of u per generation.
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u is the proportion of all A1 alleles that mutate to A2 between one generation and the next.
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If the frequency of A1 in one generation is p0
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Then
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Suppose the gene mutates in both directions and the initial allele (gene) frequencies are p ( A1 ), q ( A2 )
- Then the change of gene frequency in one generation
- This situation leads to equilibrium in gene frequency at which no further change takes place. The point of equilibrium can be found by equating the change of frequency Δ q to zero.
- pu – qv = 0
- qv = pu
- qv = (1-q)u
- qv = u – qu
- qv + qu = u
- q(v+u)=u
- q = u / (u + v)
- Similary p = v / (v + u)
- If the mutational rates of A1 to A2 ( u ) and A2 to A1 ( v ) are known at equilibrium then the frequency of A1 allele and A2 allele can be calculated directly without using conventional method of estimating gene frequency
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Last modified: Friday, 23 December 2011, 7:54 PM