Mitochondrial phylogeography of the moor frog, Rana arvalis

Abstract

The moor frog Rana arvalis is a lowland species with a broad Eurasiatic distribution, from arctic tundra through forest to the steppe zone. Its present-day range suggests that glacial refugia of this frog were located outside southern European peninsulas. We studied the species-wide phylogeographical pattern using sequence variation in a 682 base pairs fragment of mtDNA cytochrome b gene; 223 individuals from 73 localities were analysed. Two main clades, A and B, differing by c. 3.6% sequence divergence were detected. The A clade is further subdivided into two subclades, AI and AII differing by 1.0%. All three lineages are present in the Carpathian Basin (CB), whereas the rest of the species range, including huge expanses of Eurasian lowlands, are inhabited solely by the AI lineage. We infer that AII and B lineages survived several glacial cycles in the CB but did not expand, at least in the present interglacial, to the north. The geographical distribution and genealogical relationships between haplotypes from the AI lineage indicate that this group had two glacial refugia, one located in the eastern part of the CB and the other probably in southern Russia. Populations from both refugia contributed to the colonization of the western part of the range, whereas the eastern part was colonized from the eastern refugium only. The effective population size as evidenced by theta(ML) is an order of magnitude higher in the AI lineage than in the AII and B lineages. Demographic expansion was detected in all three lineages.

The postglacial recolonization of Northern Europe by Rana arvalis as revealed by microsatellite and mitochondrial DNA analyses

“…Mitochondrial DNA: An approximately 900 bp long fragment of the mitochondrial cytochrome b from 36 individuals representing 19 populations was amplified using the same primers and polymerase chain reaction (PCR) conditions as in Babik et al (2004). The primers were ralu1 (5 0 -AACCTTATGACCCCAACAATACG-3 0 ; Bos and Sites, 2001) and a modified H15502 (5 0 -GGG TTAGCTGGTGTAAAATTGTCTGGG-3 0 ; Tanaka-Ueno et al, 1998).…”

“…T Knopp and J Merilä described earlier (Babik et al, 2004), whereas five new ones were discovered (RA1-RA5, GenBank accession numbers EU523748-EU523752). All haplotypes differed from each other by one or two codon substitutions (Table 2).…”

“…Together with Rana temporaria, it is the only frog species inhabiting the northern parts of Fennoscandia (Fog et al, 1997). Owing to its highly variable morphology and coloration, R. arvalis has often been the subject of studies of geographic variation and phylogeography (Stugren, 1966;Fog et al, 1997;Rafiń ski and Babik, 2000;Babik et al, 2004;Knopp et al, 2007). On the basis of morphological data Stugren (1966) concluded that the Scandinavian moor frogs most likely originate from the East, whereas the distribution of color morphs led Fog et al (1997) to suggest a bidirectional recolonization of Fennoscandia.…”

“…On the basis of morphological data Stugren (1966) concluded that the Scandinavian moor frogs most likely originate from the East, whereas the distribution of color morphs led Fog et al (1997) to suggest a bidirectional recolonization of Fennoscandia. In a large-scale study of the mitochondrial phylogeography of R. arvalis, Babik et al (2004) found evidence for weak differentiation among western and eastern Eurasian populations. However, as samples from northern Fennoscandia were not part of that study, the recolonization route of moor frogs to Fennoscandia remains unresolved.…”

Amphibian phylogeography: a model for understanding historical aspects of species distributions

“…Both of these anurans currently range further north than the Arctic Circle. MtDNA (cytb) studies of R. arvalis identified three main lineages (Babik et al, 2004), all of which occur at its southerly range limit in the Carparthian basin. Only one of these lineages, however, occurs across the large expanse of the moor frog's range in northern Europe.…”