title: Population structure of two closely related pelagic cichlids in Lake Victoria, Haplochromis pyrrhocephalus and H. laparogramma.
abstract: Cichlid fishes in Lake Victoria show spectacular diversification that is thought to be recent. Therefore, by investigating those fishes, we may be able to elucidate recently completed or ongoing speciation processes. We studied the population structures of two closely related pelagic cichlid species, Haplochromis pyrrhocephalus and H. laparogramma, using a mitochondrial DNA locus and 12 nuclear microsatellite loci as putative neutral markers. Ten and two populations of H. pyrrhocephalus and H. laparogramma, respectively, were sampled from the southern part of Lake Victoria. We grouped those 12 populations into four mutually differentiated regional populations, one of which consisted of the two H. laparogramma populations. The levels of differentiation were substantial at the mitochondrial locus (F(ST) = 0.03-0.54), but very low at microsatellite loci (R(ST) = 0.008-0.116). The data from both types of loci indicated that the regional population of H. laparogramma was first separated from those of H. pyrrhocephalus if we set aside one erratic population of H. pyrrhocephalus. The data also suggested recent population expansions of the two species, the time scales for which were estimated to be on the order of 10(4)-10(5) years. These data suggested that dynamic speciation processes accompanied occasional spawning of new species and population size changes in this lake.
authors.affiliation: Department of Biology, Faculty of Sciences, Kyushu University, Ropponmatsu, Fukuoka 810-8560, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Maeda
authors.forename: Miyuki
authors.initials: M
authors.lastname: Takeda
authors.forename: Koichi
authors.initials: K
authors.lastname: Kamiya
authors.forename: Mitsuto
authors.initials: M
authors.lastname: Aibara
authors.forename: Semvua Isa
authors.initials: SI
authors.lastname: Mzighani
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Nishida
authors.forename: Shinji
authors.initials: S
authors.lastname: Mizoiri
authors.forename: Tetsu
authors.initials: T
authors.lastname: Sato
authors.forename: Yohey
authors.initials: Y
authors.lastname: Terai
authors.forename: Norihiro
authors.initials: N
authors.lastname: Okada
authors.forename: Hidenori
authors.initials: H
authors.lastname: Tachida
mesh_terms: D000818:Animals; D023681:Cichlids / Q000145:classification* / Q000235:genetics* / Q000502:physiology; D004272:DNA, Mitochondrial / Q000235:genetics; D017753:Ecosystem; D005260:Female; D049810:Genetic Speciation; D005828:Genetics, Population; D019901:Locus Control Region; D008297:Male; D018895:Microsatellite Repeats; D010802:Phylogeny; D015030:Zimbabwe
chemical_list: D004272:DNA, Mitochondrial