Question

Which observation is not evidence of positive selection in DNA sequences?

a. Direct observation that individuals with specific alleles leave behind more descendants
b. A dN/dS ratio much greater than one
c. Clocklike sequence evolution in protein coding genes
d. A greater d/π ratio at synonymous sites than at nonsynonymous sites
e. Unusually high sequence divergence in a localized population

Answer 1

Question

The positive selection is a type of selection by which advantageous changes occur in the DNA sequence. Usually smaller variation is present in the individual of a given population but higher sequence divergence is not indicator of positive selection. Other than this, dN/dS (ratio of non-synonmous site to synonmous site) value greater than 1, individual with specific allele having more frequency than other allele are the evidence of positive selection. Hence, incorrect option is e.