Geographic Variation of Six Allozyme Loci in Drosophila Melanogaster: An Analysis of Data from different Continents

Abstract

Based on data from 70 literature sources, the frequencies of common alleles at six allozyme loci were examined in Drosophila melanogaster populations from five geographic regions: North America (including Central America), South America, Europe-Africa, Asia, and Australasia. The analyzed loci were Adh, Odh, Gpdh, G6pd, Pgd, and Est-6, which have been previously reported by other authors to show latitudinal variation in North America, Eurasia and Australasia. We found five parallel latitudinal clines for AdhF and three clines for GpdhS in five geographic regions as well as four clines for G6pdF, three clines for Est-6S, and two clines for OdhF and PgdF in four regions (data from South America for G6pd, Odh, Est-6, and Pgd were not available). Such pattern of variation confirmed the possibility that considered allozyme polymorphisms are maintained by climatic selection. Significant differentiation of mean allele frequencies among geographic regions was in agreement with current evidence on history of D. melanogaster worldwide dispersion.

TheperiodGene Thr-Gly Polymorphism in Australian and AfricanDrosophila melanogasterPopulations: Implications for Selection

“…Latitudinal clines are not observed on all continents at allozyme loci thought to be under climatic selection (Bubliy et al 1999). In Australia, however, we have observed a spatial pattern of distribution for the frequency of the (Thr-Gly) 20 allele that is reminiscent of the similar cline observed in Europe with this variant .…”

Infestation of a novel host plant by Tephritis conura (Diptera: Tephritidae) in northern Britain: host-range expansion or host shift?

“…There is, however, no indication for selection to different temperature regimes (e.g. Beckenbach and Prakash 1977;Malpica and Vassallo 1980;McKenzie et al 1994;Feder et al 1997;Bubliy et al 1999) as no altitudinal or latitudinal temperature gradients exist within either of the C. oleraceum or C. heterophyllum host-race populations in continental Europe. Important for preference adaptations may be genes related to odour and/or taste (e.g.…”

“…Potential factors restricting diet breath include natural enemies (Menken et al 1992), interspecific competition (Denno et al 1995), physiological constraints (Rosenthal and Berenbaum 1992) or the need to adapt to the host's morphology (Diegisser et al 2007) or phenology (Feder et al 1993;Dambroski and Feder 2007). The most proximate cause determining an insect's host range, however, is its behaviour (Bernays and Chapman 1994;Gassmann et al 2006); whether or not a host plant is utilised as oviposition substrate depends on the female's host choice. The permanent incorporation of a novel host plant into the repertoire of a phytophagous insect therefore involves at least modification in host preference, but may also require that the insect adapts specifically to the new host's ecology and physiology.…”

Allozyme polymorphism in Drosophila

“…The frequency of Est-6-S decreased toward center of the continent and was positively correlated with temperature of coldest month. Bubliy et al (1999) analyzed six allozyme loci in D. melanogaster from five geographical regions: North America, South America, Europe-Africa, Asia and Australia for latitudinal variations. They found five parallel latitudinal clines for Adh-F and three clines for a-Gpdh-S in five geographic regions as well as four clines for G6pd-F, three clines for Est-6-S and two clines for Odh-F and Pgd-F in four regions.…”