Rare phosphoglucomutase phenotypes

Abstract

Summary 1. PGM phenotypes have been determined by starch‐gel electrophoresis in more than 2000 unrelated ‘ English’ people and several smaller samples from other populations. 2. Besides the three common phenotypes (PGM 1, 2–1 and 2), eleven rare phenotypes have been identified, and their genetical basis investigated. 3. Nine of the new phenotypes, PGM 3–1, 3–2, 4–1, 4–2, 5–2, 6–1, 6–2, 7–1 and 7–2, appear to represent heterozygous combinations of one or another of a series of rare alleles, PGM 3 1 , PGM 4 1 , PGM 5 1 , PGM 6 1 and PGM 7 1 , with either PGM 1 1 or PGM 2 1 . Each of these alleles probably determines the formation of two new isoenzyme components which are homologous with components a and c determined by PGM 1 1 and components b and d determined by PGM 2 1 . 4. The ‘Atkinson’ and ‘Palmer’ phenotypes are thought to represent heterozygotes for alleles at a different locus, PGM 2 . The common allele at this locus is designated PGM 1 2 and the postulated genotype for the ‘Atkinson’ phenotype is PGM 1 2 PGM 2 2 and for the ‘Palmer’ pheno‐type is POM 1 2 PGM 3 2 . It is suggested that PGM 1 2 determines isoenzyme components e, f and g and that PGM 2 2 and PGM 3 2 each determine three isoenzyme components which are electrophoretically different from but homologous with e, f and g . 5. The ‘Atkinson’ phenotype appears to have an appreciable incidence in Negro populations and has so far not been observed in any non‐Negro group.