Study of genetic diversity in urchins in the mtDNA control region
We investigated phylogeographic structure and mitochondrial diversity of the Northern white-breasted hedgehog (Erinaceus roumanicus) across the Balkan-Carpathian region and placed these patterns in a broader Erinaceus context shaped by Pleistocene climate oscillations and postglacial contact zones. We sequenced the mtDNA control region (CR) from 131 road-killed hedgehogs collected in Hungary (n=70) and Serbia-Montenegro (n=61), aligned 381 bp, and combined them with 357 GenBank records for comparative network analyses (total n=488). Diversity metrics, FST and AMOVA, sPCA, maximum-likelihood phylogeny, and minimum-spanning network were used to infer structure and demography. Hungarian and Serbian-Montenegrin groups each harbored 17 haplotypes; haplotype diversity was high overall (Hd = 0.885 ± 0.017; p = 0.005), with higher Hd in Serbia-Montenegrin group (0.916 ± 0.017) than Hungarian population (0.767 ± 0.038). Tajima's D values were negative but nonsignificant, whereas Fu's Fs was strongly negative and significant in the combined and country-level datasets, indicating recent expansion or an excess of rare variants. Mismatch distributions supported this contrast: Serbian-Montenegrin fit a unimodal expansion, while Hungarian group showed a multimodal profile consistent with population substructure or demographic stability. AMOVA attributed most variation to within-population differences (88.04%), increasing among-population structure under spatial grouping (16.81%), and pairwise F ST revealed generally low differentiation but localized contrasts (e.g., Central Hungary vs. North-Central Serbia). Phylogenetic and sPCA results showed interspersed Hungarian and Serbian haplotypes, indicating only moderate geographic partitioning. The global network featured large, central haplotypes (e.g., Hap_1, Hap_16) and regionally compact Balkan/Carpathian clusters, consistent with refugial persistence and postglacial range expansion; the Carpathian Basin emerged as a genetic bridge linking Balkan lineages to more northern populations. Taken together, our findings support a scenario in which multiple southern refugia and secondary contacts (which are well documented for E. europaeus and E. roumanicus in Central vs. Russian-Baltic zones) have jointly shaped contemporary Balkan-Carpathian hedgehog diversity, with high mitochondrial variation, signals of recent expansion in the south, and only moderate spatial structuring across political borders.