The amount of polymorphism and genetic differentiation in natural populations of the haploid liverwort Conocephalum conicum.

Abstract

Natural populations of diploid organisms are expected to be more polymorphic than haploid organisms under most selection models. To test this prediction and to obtain data concerning the amount of allozyme polymorphism in a haploid plant, 2 natural populations of the haploid liverwort C. conicum were examined by starch gel electrophoresis. Abundant genic variability was found within local populations in Japan: 7 of 11 loci. Average heterozygosity of these 11 loci was 0.167. This value is similar to those obtained for various kinds of diploid organisms. Gene identity (I) between the 2 populations was 0.994, and another measure of genetic differentiation, Gst was 0.018, indicating virtually no genetic differentiation between the populations. High levels of genic variability and low levels of genetic differentiation in these haploid plants are consistent with a hypothesis of selective neutrality of allozyme polymorphisms, although other possible explanations cannot be excluded.