Allopatric Origin of Sympatric Populations of Lake Whitefish (Coregonus clupeaformis) as Revealed by Mitochondrial-DNA Restriction Analysis

Abstract

In the paper, restriction-fragment length polymorphisms in mitochondrial DNA (mtDNA) were studied to test the hypothesis that sympatric populations of lake whitefish in the Allegash basin have recently diverged through sympatric speciation. Thirteen restriction enzymes were used to analyze mtDNA of 156 specimens representing 13 populations from eastern Canada and northern Maine where normal and dwarf phenotypes of whitefish exist in sympatry and allopatry. Two monophyletic assemblages of populations that exhibit different geographic distributions were identified. One showed an eastern distribution that expands from Cape Breton to the Allegash basin and the other exhibits a more western distribution. The Allegash basin was the only area of overlap. The western assemblage exhibited the normal size phenotype in all cases, whereas the eastern assemblage exhibited the normal size phenotype in allopatric conditions and the dwarf size phenotype in sympatry. The existence of sympatric pairs in the Allegash basin result from the secondary contact of two monophyletic groups of whitefish that evolved allopatrically in separate refugia during the last glaciation events. The weak mtDNA difference of sympatric pairs suggests that speciation of lake whitefish in eastern North America was accompanied by only minor alterations of the ancestral gene pool.

Seasonal and ontogenetic variations in resource use by two sympatric Arctic charr morphs

“…The origin of polymorphism in Arctic charr and other freshwater fish has been explained by several hypotheses, ranging from allopatric divergence under geographical isolation during the last Ice Age, to divergent natural selection in sympatry (Nyman et al 1981;Klemetsen 1984;Bernatchez and Dodson 1990;Lu and Bernatchez 1999;Schluter 2000;Dieckmann et al 2004). Sympatric speciation has become increasingly accepted during the past decades, and the link between ecological differentiation and reproductive isolation seems particularly important in the evolution of postglacial fishes (Schluter 2001).…”

Does Breeding Site Fidelity Drive Phenotypic and Genetic Sub-Structuring of a Population of Arctic Charr?

“…However, empirical evidence shows a sympatric origin for divergence of some freshwater fish, for example the African cichlids, (Schliewen et al, 1994) although an allopatric origin has been suggested for others (see e.g. Bernatchez and Dodson, 1990 on Lake Whitefish Coregonus clupeaformis). Theoretical objections to the process of sympatric divergence have now largely been resolved (see Tregenza and Butlin, 1999) and a number of models proposed that identify a significant role for resource acquisition in evolutionary divergence in sympatry (Schluter, 1996;Dieckmann and Doebeli, 1999;Kondrashov and Kondrashov, 1999).…”

Morphology and mitochondrial DNA variation of the Siberian whitefish Coregonus lavaretus pidschian (Gmelin) in the upstream water bodies of the Ob and Yenisei Rivers

“…The genetic distances between the studied populations were less than those observed for C. lavaretus from Polish lakes (Kohlmann et al 2005). In addition, the weak mtDNA divergence between sympatric pairs of C. l. pidschian and C. l. pravdinellus species suggests that their speciation was accompanied by only minor alterations of the ancestral gene pool, as was reported for the lake whitefishes in eastern North America (Bernatchez and Dodson 1990). Probably, these sympatric morphs evolved allopatrically in separate refugia and independently colonised Lake Teletskoye.…”

“…The occurrence of many whitefish haplotypes and morphs in the lakes may result from a historical mixing of different populations and lineages and their secondary contact, as it was suggested for the whitefishes of Europe and North America (Bernatchez and Dodson 1990;Bernatchez and Wilson 1998;Kohlmann et al 2005;Østbye et al 2005). To conclude, the water bodies of the southern part of Siberia represent a secondary contact zone for the distinct phylogenetic lineages of Coregonus lavaretus pidschian.…”

“…The genus Coregonus is a good model to study ecological speciation and evolution due to its considerable phenotypic variation and life history traits. Observed morphological differences among sympatric and allopatric whitefish species pairs, and the reproductive isolation between them, may have arisen from adaptive radiation or secondary contact between one or more different lineages (Bernatchez and Dodson 1990;Turgeon et al 1999;Østbye et al 2005;Mehner et al 2010). However, morphological and phylogenetic studies on Siberian whitefish populations have not yet been carried out.…”