Abstract
With two copies of every gene, a diploid organism is
able to mask recessive deleterious mutations. In this
paper we present the analysis of a two-locus model
designed to determine when the masking of deleterious
alleles favors the evolution of a dominant diploid
phase in organisms that alternate between haploid and
diploid phases (älternation of generations"). It
is hypothesized that diploidy will be favored whenever
masking occurs ("the masking hypothesis"). Using
analytical methods, we confirm that this masking
hypothesis is essentially correct under free
recombination: as long as the heterozygous expression
of deleterious alleles is sufficiently masked by the
wild-type allele, diploidy is favored over haploidy.
When the rate of recombination is lower, however,
diploidy is much less likely to be favored over
haploidy. In fact, according to our model, the
evolution of diploidy is impossible without significant
levels of recombination even when masking is fairly
strong.
Users
Please
log in to take part in the discussion (add own reviews or comments).