A molecular phylogeny for the Drosophila melanogaster subgroup and the problem of polymorphism data.
Drosophila melanogaster belongs to a closely related group of eight species collectively known as the melanogaster subgroup; all are native to sub-Saharan Africa and islands off the east coast of Africa. The phylogenetic relationships of most species in this subgroup have been well documented; however, the three most closely related species, D. simulans, D. sechellia, and D. mauritiana, have remained problematic from a phylogenetic standpoint as no data set has unambiguously resolved them. We present new DNA sequence data on the nullo and Serendipity-alpha genes and combine them with all available nuclear DNA sequence data; the total data encompass 12 genes and the ITS of rDNA. A methodological problem arose because nine of the genes had information on intraspecific polymorphisms in at least one species. We explored the effect of inclusion/exclusion of polymorphic sites and found that it had very little effect on phylogenetic inferences, due largely to the fact that 82% of polymorphisms are autapomorphies (unique to one species). We have also reanalyzed our previous DNA-DNA hybridization data with a bootstrap procedure. The combined sequence data set and the DNA-DNA hybridization data strongly support the sister status of the two island species, D. sechellia and D. mauritiana. This at least partially resolves what had been a paradox of parallel evolution in these two species.
Caccone
A
A
Department of Biology, Yale University, New Haven, Connecticut 06520-8104, USA.
Moriyama
E N
EN
Gleason
J M
JM
Nigro
L
L
Powell
J R
JR
D000818:Animals; D004247:DNA / Q000737:chemistry; D004330:Drosophila / Q000145:classification / Q000235:genetics; D004331:Drosophila melanogaster / Q000145:classification / Q000235:genetics*; D017344:Genes, Insect; D017403:In Situ Hybridization / Q000379:methods; D008954:Models, Biological; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics; D010802:Phylogeny; D011110:Polymorphism, Genetic; D012335:RNA, Ribosomal
D009687:Nuclear Proteins; D012335:RNA, Ribosomal; D004247:DNA