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We studied mitochondrial DNA variation in the European rabbit through the examination of restriction fragment length polymorphism in 526 individuals from 20 locations spread across the Iberian Peninsula. Digestion with eight enzymes of a 1120-bp fragment comprising most of the cytochrome b gene resolved 38 different haplotypes. These haplotypes were distributed in two highly divergent clades, with different but overlapping geographical distributions, and with comparable levels of within-clade variation. The overall phylogeographical pattern suggests a history of long-term regional isolation of two groups of rabbit populations, compatible with the recognition of two subspecies within the Iberian Peninsula, followed by recent contact and admixture. The underlying cause is sought in the alternation of glacial and interglacial periods in the late Pleistocene. [ABSTRACT FROM AUTHOR]

Abstract Infectious diseases and their demographic consequences are thought to influence the genetic diversity of populations. In Europe, during the last 50 years, the European rabbit (Oryctolagus cuniculus) has suffered two important viral epizootics: myxomatosis and rabbit viral haemorraghic disease (RVHD). Although mortality rates were very high, the impact of these diseases on genetic diversity has never been assessed directly. The subject of this paper is a wild rabbit population in France, which has been studied since the beginning of the 1980s. The first outbreak of RVHD occurred in 1995 and provoked a demographic crash. The population, sampled for the first time in 1982 and 1994, was sampled again at the end of 1996 to examine the impact of the epizootic on genetic diversity. In spite of the observed high mortality rate (≈ 90%), analysis of 14 polymorphic loci (allozymes and microsatellites) showed no loss in genetic diversity after the epizootic. Determination of temporal changes in allele frequencies indicated that the population evolved under genetic drift. The temporal method of Waples demonstrated a significant decrease in the effective population size (Ne) correlated with the demographic crash due to the epizootic. However, the population had only been studied for two generations after the epizootic and the remnant population size probably stayed high enough (≈ 50 individuals) to keep its genetic diversity at the precrash level. These results suggest that, contrary to what is usually thought and in spite of the subsequent high mortality rates, past epizootics (especially myxomatosis) may have had little effect on the genetic diversity of wild rabbit populations in Europe. [ABSTRACT FROM AUTHOR]