Historical Biogeography of the Drosophila melanogaster Species Subgroup

Abstract

that in recent historical time, i.e., Pleistocene, the geographic ranges of D. melanogaster and D. simulans were completely disjunct. Hence, the two cryptic species are assumed to have been allopatric species in the Afrotropical region, and indeed to some extent they remain so. Drosophila erectaDrosophila erecta has been recorded from the south and mid Ivory Coast: Yale at the bottom (400 m) of Mt. Nimba at the border of Guinea,

Molecules versus morphology: the detection of selection acting on morphological characters along a cline in Drosophila melanogaster

“…Although populations of Drosophila have been studied extensively with the objective of estimating levels of gene flow between populations (for reviews see David & Capy, 1988;Lachaise et al, 1988;Singh, 1989;Singh & Long, 1992) only a few studies have combined estimates of gene flow and morphological character differences to understand the nature of selection acting on morphological traits (Prout & Barker, 1993;Spitze, 1993). The test of Prout & Barker (P-B test) is in many ways similar to the earlier Lewontin-Krakauer test (1973), but it avoids the phylogenetic pitfall pointed out by Robertson (1975) by averaging over loci in estimating character and allozyme population subdivision.…”

Mitochondrial DNA variability in Drosophila simulans: quasi absence of polymorphism within each of the three cytoplasmic races

“…They probably originated from a common Afrotropical ancestor a few million years ago (Lachaise et al, 1988) and have spread to most of the world in the recent past with the aid of human transport (David and Tsacas, 1981;Parsons, 1983). D. melanogaster shows great geographic variation and such "racial" differentiation may have allowed the colonization of places with very different climates.…”

Molecular similarity of Drosophila melanogaster alcohol dehydrogenase thermostable alleles from populations on different continents

“…Far fewer natural populations have been scored for Adh thermostable alleles than for Adh ', but in the data that are available the highest frequency of Adh FChD is in southern China where it reaches 30 per cent (Jiang et a!., 1989). Although the allele occurs at low frequency in the Canary Islands (Hernández et a!., 1986) it has not so far been reported from the African continent where the melanogaster subgroup originated (Lemeunier et a!., 1985;Lachaise et a!., 1988).…”

“…In populations sampled in North America and Australia, where most data are available, the frequencies of AdhF thermostable alleles tend to be less than 5 per cent (Sampsell, 1977; Lachaise et a!. (1988).…”