Table 1. Statistics summarizing the data.

Age (cal. yrs BP)	Seg.Sites	Haplotypes	Pairw. Diff.	Nucleo. Div.	Hapl. Div.
Cytochrome B - 282bp
Modern	1	2	0.467	0.00165	0.467
11.500	6	6	0.689	0.00244	0.516
15.200	8	6	1.868	0.00663	0.737
25.200	12	7	3.736	0.01325	0.901
Control Region - 426bp
Modern	1	2	0.200	0.00047	0.200
11.500	1	2	0.100	0.00023	0.100
15.200	5	4	0.679	0.00159	0.437
25.200	6	8	2.451	0.00575	0.824
Combined - 708bp
Modern	2	3	0.667	0.00094	0.600
11.500	7	7	0.789	0.00112	0.584
15.200	13	7	2.547	0.00360	0.774
25.200	18	10	6.187	0.00874	0.945

We estimated different summary statistics for the two genes separately and for the combined region. The number of segregating sites directly reflects the genetic variability and therefore the effective population size. Additionally we provided frequency based statistics such as average pairwise sequence difference. Interestingly we found higher variation in cytochrome b gene than in the control region, which is consistent with observations in modern collared lemmings [31] but in contrast to mtDNA variation in other rodents [33]. (Seg.Sites…segregating sites, Haplotypes…number of haplotypes, Pairw. Diff…average pairwise sequence difference, Nucleo. Div…nucleotide diversity, Hapl.Div…haplotype diversity).