Mitochondrial DNA diversity of the Northern Bat (Eptesicus nilssonii) in the northern Palearctic
Year: 2014
Type: article
Abstract: Several factors, such as the climate fluctuations during the Pleistocene ice age, have contributed to the geographical distribution of genetic variation in contemporary populations. Phylogeography studies the variation by connecting the genetic lineages of individuals with their geographical locations. One of the most popular markers used in these studies is mitochondrial DNA (mtDNA) due to its practical qualities. Mitochondrial DNA has revealed a whole new diversity of bat species and populations compared to conventional study methods using morphology alone. The study species, the Northern Bat (Eptesicus nilssonii), is a common, widely distributed and the most northern one of the Palearctic bat species, but its entire range has not yet been studied genetically. My aim is to study the mtDNA diversity of the Northern Bat mainly in the area of Fennoscandia and Latvia and compare this data with earlier published sequences from individuals located elsewhere in the northern Palearctic to elucidate its population structure and history. The mtDNA diversity of the Northern Bat was examined from 146 individuals, of which mtDNA was sequenced of two different mtDNA markers, cytochrome b and control region. The DNA was obtained from tissue material of live bats and museum specimens. Additional data comprised 6 Northern Bat and 13 Serotine sequences. Sequences of a sister species, the Serotine (E. serotinus), were used as an outgroup. Three geographically embedded data sets from the northern Palearctic, northern Europe and Finland, were formed for examining population structure in different geographical scales. The Northern Bat population was observed to be divided into two mitochondrial lineages; one located mostly in West (European lineage) and the other in East (Siberian lineage). These lineages seem to have diverged 0.85–1.1 million years ago based on a corrected cytochrome b distance of 1.7–2.2 %. On the control region, the European lineage showed considerable genetic diversity (π = 0.019, h = 0.966), and the Siberian lineage high haplotype diversity (h = 0.978) but relatively low nucleotide diversity (π = 0.009). The European lineage was further divided into four genetically different groups, clusters, but the Siberian lineage formed only a single cluster. The variation was geographically structured on the north European scale (ΦST = 0.07), but not on the Finnish scale (ΦST = -0.002). One of the Finnish colonies was found to comprise both lineages, while other sampled colonies consisted of only individuals of the European lineage. The European and Siberian lineages have presumably diverged in isolation through the Middle Pleistocene times, and, despite the genetic distinction between the lineages, they most likely represent interbreeding conspecific populations. Thus, the species’ nomenclature needs no changes. At the north European scale, the high nucleotide diversity observed in the European lineage resulted from the four clusters, which most likely formed in the major refugia in Europe, whereas the low nucleotide diversity in the Siberian lineage resulted from the single cluster, which presumably originated in a single refugium in Central Asia. On the Finnish population scale, both lineages were observed, but the population in general was not geographically structured. The colony comprising both lineages was most likely an indication of the lineages interbreeding. Fennoscandia was evidently recolonized by the European lineage via two routes (Denmark/Sweden and the Baltic countries), and the Siberian lineage via one (Karelia) from Russia. The lineages have come into contact for a second time in Finland and presumably in the European Russia after the end of the last glaciation. Thus, the Pleistocene ice age was a substantial contributor to the observed contemporary population structure of the Northern Bat.
Source: Työväentutkimus Vuosikirja
Author: Anna Lempiäinen
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W3008639383