Gene flow between species of Lake Victoria haplochromine fishes.
The haplochromine cichlid fishes of Lake Victoria (LV), East Africa, are a textbook example of adaptive radiation-a rapid divergence of multiple morphologically distinguishable forms from a few founding lineages. The forms are generally believed to constitute a "flock" of several hundred reproductively isolated species in a dozen or so genera. This belief has, until now, not been subjected to a test, however. Here, we compare genetic variation at 11 loci in 10 haplochromine populations of 6 different species. Although the genetic diversity in the populations is quite high, using a variety of statistical tests, we find no evidence of genetic differentiation among the populations of LV haplochromines. On genetic distance trees, populations of the same species intermingle with those of different species. At the molecular level, the species are indistinguishable from one another. Genetic comparisons with closely related species in 2 crater lakes indicate that the species within LV continue exchanging genes. These observations have important implications for phylogenetic reconstruction. The approach used in this study is applicable to other instances of adaptive radiation.
Samonte
Irene E
IE
Biology Department and Center for Natural Sciences and Environmental Research, College of Science, De La Salle University-Manila, Manila, Philippines.
Satta
Yoko
Y
Sato
Akie
A
Tichy
Herbert
H
Takahata
Naoyuki
N
Klein
Jan
J
D000351:Africa, Eastern; D000818:Animals; D002467:Cell Nucleus / Q000235:genetics; D023681:Cichlids / Q000145:classification / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000737:chemistry / Q000235:genetics; D005618:Fresh Water; D051456:Gene Flow; D049810:Genetic Speciation; D014644:Genetic Variation; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013997:Time Factors
D004272:DNA, Mitochondrial