Although viability selection directly operating at
observed enzyme gene loci seems to be obvious in
some cases, genomic associations may substantially
contribute to the above results. Partial self-fertilization,
for example, generally leads to a genomic correlation
of heterozygosity such that a heterozygote
fitness advantage at an adaptive but not necessarily
observable gene locus also affects other loci. As a
consequence, observed gene loci with no adaptive
relevance eventually show at least a slight advantage of heterozygotes or an existing overdominance is even
enlarged