A phylogeny for the principal alleles of the human phosphoglucomutase-1 locus.

Abstract

The results of phosphoglucomutase-1 (PGM1) typings by starch gel electrophoresis and subtypings by isoelectric focusing are prsented for a sample of Japanese. A distinction made on the basis of isoelectric focusing (termed + and -) is nonrandomly associated with each of the products of the 4 most common electrophoretic alleles (PGM11, PGM12, PGM13 and PGM17). The isoelectric trait cosegregates with the allele; the degree of nonrandomness of the association varies from allele to allele. The 4 alleles become 8. On the basis of these facts plus the additive nature of the pI differences between allele products and the geographical distribution of the alleles, an allele phylogeny can be constructed. The 8 alleles may be explained by 3 nucleotide substitutions involving the stem allele plus 4 intragenic recombinations between these substitutions. The potential of intragenic recombination as a cause of mutation was insufficiently appreciated.