According to the nearly neutral theory, the probability that a new mutation will

Question

According to the nearly neutral theory, the probability that a new mutation will eventually be fixed in the population (expressed as a ratio to the probability of fixation of a neutral allele) is: P(x)/P(0) = x/(1-e-x ) Where x = 2Ns. Recall that 2Ns = twice the effective population size, multiplied by the relative selection coefficient. Why did the fixation probability turn out to be a function of 2Ns, and not just a function of s? What does that tell us about how evolution works in large populations vs. small populations?

Explanation / Answer

Ans. A neutral theory states that some changes or variations in the alleles cause no harm to the individual and nor does it affect the survival or fitness of the individual.Such alleles are called neutral alleles.eg.A protein will have small variations in the sequence between population but will serve the same function.But this does not mean that the neutral alleles are unimportant but they are just selectively neutral.

In the given formula for probalityof fixation 2Ns is consider where N is the population size and s is selection coefficient.Now Fixation of gene depends upon genetic drift and natural selection.The reason we include N is evolution depends on change in frequency of a gene in a given population size. 's' is selective advantage of a particular gene.

If N is large that population is large then probability that a gene gets fixed in population will be dependent on natural selection.But if the population is less that is N is small then probability that a gene gets fixed in a population will be due to genetic drift.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.