Electrophoretic variants characteristic of heterozygotes in haploid laver Porphyra sp.

Abstract

Starch gel electrophoresis was carried out to survey the genetic variation in the haploid lavers of the Porphyra sp. claimed to be Porphyra renera. Eleven enzyme loci were resolved and scored. Eight of the eleven loci were monomorphic, while the three loci, catalase (CAT), glucosephosphate isomerase (GPI) and mannosephosphate isomerase (MPI) showed polymorphism. At the Gpi and Mpi loci, a number of lavers had electrophoretic phenotypes characteristic of heterozygotes. In order to compare with Porphyra yezoensis, the allelic frequencies were calculated on the assumption that the heterozygous phenotypes possessed two alleles. The genetic distance between Porphyra sp. and Porphyra yezoensis was 0.1511, indicating the differentiation of the subspecies level. Electrophoretic phenotypes characteristic of heterozygotes is unexpected, since Porphyra lavers are in a haploid phase. Our findings suggest that the plant is either in the diploid phase or that duplication occurs in one of the chromosome sets.