TABLE 1

Frequently used notations

SymbolUsage
b, BAlleles at a selected locus; b is a new beneficial mutation
E( )Expectation of a random variable
h Parameter describing the effect of a hitchhiking event
K Rate at which beneficial mutations sweep through the population
M Map length of each chromosome, in morgans
2 NNumber of haploid genotypes in the population
n Chromosome number
Q, PAlleles at a modifier locus affecting the rate of mutation
q, p Frequencies of the Q and P alleles
r Recombination probability between P/Q and b/B loci
s b Selection coefficient for a beneficial mutation
s d Selection coefficient for a deleterious mutation; each deleterious mutation multiplies fitness by the same factor (1 — sd)
U Deleterious mutation rate, per haploid genome, in the Q (or QQ) genetic background
Δ U Amount by which a single P allele increases the mutation rate
Û ESS mutation rate
Ū Mean mutation rate
W Fitness of the P allele relative to the Q allele
W b Component of W caused by beneficial mutations
W c Component of W caused by direct selection
W d Component of W caused by deleterious mutations
w Fitness of an individual with mutation rate U, carrying the B allele and no deleterious mutations
z Map distance