Winter temperature correlates with mtDNA genetic structure of yellow-necked mouse population in NE Poland

Abstract

We analysed a fragment (247 bp) of cytochrome b of mitochondrial DNA sequenced using 353 samples of yellow-necked mice Apodemus flavicollis trapped in seven forests and along three woodlot transects in north-eastern Poland. Our aims were to identify the phylogeographic pattern and mtDNA structure of the population and to evaluate the role of environmental conditions in shaping the spatial pattern of mtDNA diversity. We found out that three European haplogroups occurred sympatrically in north-eastern Poland. Inferences based on mtDNA haplotype distribution and frequency defined five subpopulations. The mtDNA-based structure of mice significantly correlated with winter temperature: frequency of Haplogroup 1 was positively, and that of Haplogroup 3 negatively correlated to mean temperature of January in the year of trapping. Synthesis of the published pan-European data on the species phylogeography also showed that the possibly 'thermophilous' Haplogroup 1 has the westernmost occurrence, whereas the more 'cold-resistant' Haplogroup 3 occurs much further to north-east than the other haplogroups. The observed patter may be a byproduct of the tight coevolution with nuclear genes, as we have earlier found that - in mice population in NE Poland - the spatial pattern of nuclear DNA was best explained by January temperature. Alternatively, the observed association of mitochondrial genetic variation with temperature is possible to be adaptive as cytochrome b is involved in the process of ATP production via oxidative phosphorylation.

Fig 1. The study area and trapping sites for the yellow-necked mouse Apodemus flavicollis mtDNA analyses in NE Poland.

Augustów (AUG), Białowieża (BIAL), Borki (BOR), Knyszyn (KNYSZ), Mielnik (MIEL), Pisz (PIS), and Rominta (ROM) forests as well as three transects (T) among four of them: Augustów−Knyszyn (TAK), Knyszyn−Białowieża (TKB), and Białowieża−Mielnik (TBM).

Fig 2. Upper panel: Neighbour–joining tree phylogenetic tree of cyt b fragment of mtDNA haplotypes of yellow-necked mouse found in this study.

Lower panel: Median joining network constructed in program NETWORK. Dashes denote number of mutation steps among haplotypes.

Fig 3. Maximum likelihood tree of cyt b fragment of mtDNA haplotypes of yellow–necked mouse found in NE Poland (H1 − H24) and recorded in other studies.

Bootstrap values shown if greater than 50%. Sequences from GenBank are coded according to the country location. List of data and sources in S2 Table.

Fig 4. Geographic distribution of cyt b haplotypes of yellow-necked mice based on sequences derived from this study and the analoque cyt b fragment from the published data (sources in S2 Table).

Lower panel: Mean January temperature (°C) in each of the sampling points, where the individuals belonging to haplogroups 1–3 were found. Shapes of symbols indicate assignment to haplogroups based on Maximum Likelihood phylogenetic tree: circles–Haplogroup 1, triangles–Haplogroup 2, squares Haplogroup 3. In dark grey: the range of the yellownecked mouse in Europe (from: www.iucnredlist.org).

Fig 5

Five subpopulations (S1–S5) of yellow-necked mouse in north-eastern Poland, based on mtDNA haplotype frequency, delimited by SAMOVA (left panel). Proportions of mtDNA haplogroups (clades) in each of the defined subpopulation (right panel). Black points refer to trapping sites.

Fig 6

Relationships between mean temperature of January in the year of trapping in 10 studied region in NE Poland and probability of yellow-necked mouse assignment to Haplogroup 1 (upper panel) and Haplogroup 3 (lower panel) − results of the most parsimonious generalized linear mixed models (GLMMs) presented in Table 3.