Global Survey of Mitochondrial DNA Sequences in the Threespine Stickleback: Evidence for Recent Migrations

Abstract

Phylogenetic analyses of mitochondrial DNA (mtDNA) sequences were used to assess the matriarchal genetic structure of the threespine stickleback, Gasterosteus aculeatus. A 747 base-pair (bp) fragment of the cytochrome b was sequenced from 36 individuals collected from 25 localities in Europe, North America, and Japan. Two major divergent clades were revealed: one widespread in Japan but with representatives in some Alaskan and British Columbian lakes and the other common in Europe and North America. A simple diagnostic test using the polymerase chain reaction (PCR) and a restriction enzyme was used to assay additional individuals, confirming the absence of the Japanese clade in the Atlantic basin. Geographic distribution of mtDNA variation suggests (1) a recent origin of the Atlantic populations, and (2) support for previous hypotheses about the existence of Pleistocene refugia for freshwater fishes in Alaska and British Columbia. Silent substitution rates were used to date the colonization of the Atlantic at 90,000 to 260,000 yr before present, which conflicts with earlier dates implied by the fossil record. The recent replacement of Atlantic mitochondrial lineages suggested by our data may be explained by severe reduction or extinction of northern Atlantic populations during the Pleistocene, followed by a recent reinvasion from the Pacific. With a global perspective of the distribution of genetic variation as a framework, meaningful comparisons at a smaller geographical scale will now be possible.

Rapid adaptive evolution of colour vision in the threespine stickleback radiation

“…Previous studies show that phylogenies of freshwater stickleback populations in British Columbia based on putatively neutral markers are well approximated by a star phylogeny (e.g. [27]). …”

Physiological and genetic basis for variation in migratory behavior in the three-spined stickleback, Gasterosteus aculeatus

“…First, the G. aculeatus species complex includes both anadromous and freshwaterresident forms of G. aculeatus (Bell and Foster 1994;McKinnon and Rundle 2002). The ancestral forms of G. aculeatus are considered anadromous, whereas freshwater-resident forms have evolved independently from the anadromous forms in multiple lineages (Haglund et al 1992;Orti et al 1994;McPhail 1999, 2000;McKinnon et al 2004;Colosimo et al 2005). The anadromous forms of G. aculeatus usually migrate to freshwater or estuaries in spring (Table 1), while juveniles migrate to the sea in fall (Table 2), although there are substantial variation in the timing of migration (Tables 1, 2).…”

Cryptic genetic variation and paraphyly in ravens

“…(b) Comparisons with genetic breaks found in other species Our ¢ndings of a distinct genetic break without apparent phenotypic di¡erentiation in common ravens is similar to cryptic genetic variation documented in many other taxa (reviewed in Avise 2000). However, few previous studies have shown such a deep mitochondrial split that is geographically structured but has such a wide contact zone (but see Orti et al 1994, sticklebacks; R. C. Fleischer, unpublished data, Asian elephants). For example, Carolina chickadee haplotypes completely shift from one mitochondrial type to the other across a relatively narrow 400 km east^west transect (Gill et al 1993(Gill et al , 1999; also see Patton & da Silva 1998).…”