Adaptation often involves the acquisition of a large number of genomic changes which arise as mutations in single individuals. In asexual populations, combinations of mutations can fix only when they arise in the same lineage, but for populations in which genetic information is exchanged, beneficial mutations can arise in different individuals and be combined later. In large populations, when the product of the population size N and the total beneficial mutation rate U b is large, many new beneficial alleles can be segregating in the population simultaneously. We calculate the rate of adaptation, v, in several models of such sexual populations and show that v is linear in N U b only in sufficiently small populations. In large populations, v increases much more slowly as log N U b . The prefactor of this logarithm, however, increases as the square of the recombination rate. This acceleration of adaptation by recombination implies a strong evolutionary advantage of sex.
In REF , several different modes of recombination were examined and it was shown that in all models, when the population size is large, the rate of adaptation has a logarithmic dependency on N · u (population size times beneficial mutation rate), rather than linear.
Rate of Adaptation in Large Sexual Populations
arXiv: Populations and Evolution
Biology Medicine Physics