Genetic Conditions Which Promote or Retard the Formation of Species
This extract was created in the absence of an abstract.
Excerpt
Introduction
With respect to a particular autosomal gene or chromosomal structure a diploid organism may be either heterozygous or homozygous. If selection favors the heterozygous state at any particular locus, the result, barring accidents of random drift, will be a balanced condition in which both alleles persist indefinitely in the population. On the other hand, when a particular homozygous state is favored, selective and random drift will both tend to fix the allele which is represented twice in the favored homozygote.
This paper will concern itself with a relatively simple working hypothesis relating to these two kinds of genetic adjustment and the formation of species. The hypothesis will be stated in the following paragraphs in an outline form and will then be expanded somewhat and certain evidence for it adduced. The material presented is intended to be merely exemplary; no attempt has been made in this short paper to apply...
