MHC class II DQA gene variation across cohorts of brown hares (Lepus europaeus) from eastern Austria: Testing for different selection hypotheses

We have studied the temporal variation (1999–2007) in the MHC class II DQA gene and 8 microsatellites across 8 cohorts in a population of brown hare (Lepus europaeus) from eastern Austria. Our results show no significant temporal changes in allele frequencies both in microsatellites and the DQA gene. Although positive selection on a larger evolutionary time scale has occurred in DQA, we have not observed evidence of contemporary balancing selection in this gene. Our results are not compatible with the negative frequency-dependent selection or the variable selection in time hypotheses within a timeframe of 8 consecutive generations. However, selection heterogeneity in space occurs. The studied cohorts have probably not been exposed to strong effects of parasites and pathogens during the period of this study, as indicated by our endoparasite counts and infection data. Furthermore, the most common DQA allele (Leeu-DQA*06) was found to be in a stable frequency equilibrium which is consistent with the occurrence of stabilizing selection. This could indicate that major selective agents have been rather constant in their frequency across our temporal samples.