The adaptive significance of electrophoretic mobility in phosphoglucose isomerase (PGI)

Abstract

A literature search was conducted for evidence of natural selection having acted on PGI loci at two levels: (1) on polymorphisrns, and ( 2 ) on homologous loci in closely related species during the speciation process. The results indicated that at both levels there is a significant relationship between relative electrophoretic mobility (probably net charge) and environmental conditions, such that the more anodal allozyme/isozyme is favoured under a suite of conditions comprising one or more of the following: increased temperature, increased salinity, increased exposure and risk of desiccation, and reduced oxygen availability.

Inherited stress resistance and longevity: a stress theory of ageing

“…This suggests at least one locus in natural populations of importance in determining resistance to stress. This situation is not surprising since in vitro biochemical studies of PGI allozymes suggest that this enzyme is a direct target of selection of stress (Watt, 1983;Riddoch, 1993).…”

Genetic differentiation among populations of Myopus schisticolor (the wood lemming) — isozyme variation

“…There is an increase in the number of studies which indicate that natural selection acts on PGI in different species (Riddoch, 1993). It must be noted that all the examples of the selective significance of PGI were detected for poikilotherms.…”

Regional structuring of genetic variation in short-lived rock pool populations of Branchipodopsis wolfi (Crustacea: Anostraca)

“…Kimura 1983;Futuyama 1986; but see e.g. Riddoch 1993;Johannesson et al 1995). It is very unlikely that and geographic distance at this site.…”

“…As in some cases (e.g. Riddoch 1993;Johannesson et al 1995) allozyme frequencies correlated to environmental variables, we have tested for an association between allele frequencies and all environmental variables measured. Associations between environmental variables and genetic characteristics (genetic diversity measures, allele frequencies) were assessed with principal component analysis run for a correlation matrix in a varimax rotation mode and with the Pearson correlation coefficient with Bonferroni adjusted probabilities (Systat 8, SPSS Inc.).…”

“…In obligately sexual brine shrimps, the reported levels of population differentiation varied between F st =0.24 in Artemia franciscana and F st =0.12 in A. salina (Abreu-Grobois and Beardmore 1982;AbreuGrobois 1987), whereas only a weak overall genetic differentiation was observed among nine A. sinica populations (F st =0.02-0.25) separated by as much as 1000 km the measured correlation between average pool temperature and allele frequency at three loci (GPI, PGM, AAT) at the same time is the result of selection, as this association is usually only manifested at the GPI locus (Riddoch 1993). It is, therefore, more likely that this association is caused by chance due to the low genetic diversity at the Th site that also held pools with the highest average water temperature.…”