In contrast only one allele was unique to the contemporary samples, and was found at lower frequencies (2005: 0.022 and 2007: 0.059; see Additional file 2 Figure S1).
The average successful amplification and scoring rate per locus was 97.5% for contemporary samples and 92.3% for historical ones with no difference between loci or populations.
As we were particularly interested in loci under selection between the clusters, we followed up with pairwise comparisons of the clusters (here only including the 'pure' contemporary samples) and non-hierarchical tests among the samples within each cluster (historical and contemporary separately).
We used the same time periods as described above to represent a serial sampling of the population at four time points (t0 -t3), with t0 representing the contemporary sample and t3 the oldest of the ancient samples.
We sampled historical and contemporary samples from western and southern Texas to examine how (i) genetic diversity, (ii) genetic differentiation and (iii) effective population size have changed over time.
Temporal estimates of the effective population size (Ne) based on historical and contemporary samples, assuming open populations and a generation length (T) of 2 years.
Pairwise FST estimates between museum and contemporary samples were moderately large and highly significant (all FST > 0.1, P < 0.001; Table 2), but there was no significant differentiation between the 1997 and 2011 populations (FST = 0.001, P = 0.2; Table 2).
We thank A.E. Lomborg for providing the contemporary samples from 2005 and the Natural History Museums in Aarhus and Copenhagen, Denmark, for kindly providing leg samples of M. arion from their collections, in particular Prof. N.P. Kristensen, Dr. O. Karsholt and Dr. S. Kaaber.
They are accompanied by contemporary samples of wallpapers and textiles, objects like ceramic pots, magazines and trade literature from interior furnishings suppliers like rug and drapery manufacturers whose do-it-yourself, dream-house sales catalogs were like supplemental family Bibles in suburban homes.
Because the sample sizes differed, we resampled 14 genotypes from the contemporary samples 10,000 times and estimated mean He.
In the comparison between contemporary samples from Møn and Sweden nine microsatellite loci were used; Macu8, Macu9, Macu11, Macu15, Macu17, Macu20, Macu26, Macu44 and Macu45 [with genotype data already existing for the Swedish populations, see [ 20]].
