Allozyme variability in autochthonous colonies of Swiss Alpine marmots (Marmota m. marmota): A confirmation of the "species-wide bottleneck hypothesis"? [Variabilité des allozymes des colonies autochtones de marmottes alpines : une confirmation de « l’hypothèse d’un important goulot d’étranglement »].

Résumé

Allozymic variability of 303 Alpine marmots (Marmota m. marmota) from three local populations of the Swiss canton Grisons was studied by horizontal starch gel electrophoresis to corroborate or refute the "species-wide bottleneck hypothesis" of this species. This hypothesis has previously been suggested in order to explain the low genetic variability on the allozyme level found so far in all regional populations of this species (Preleuthner and Pinsker 1993). Based on 25,436 genes presently studied, polymorphism was found at eight of 48 loci screened. All polymorphic loci were diallelic. Overall rate of polymorphism (16.7%) was significantly higher than the value based on all populations screened earlier from the Eastern and from parts of the Western Alps. Population-specific rates of polymorphism (8.33 - 14.58 %, expected heterozygosities (2.3 - 3.8 %) and H(e) / P -rates were well within the ranges found in many terrestrian mammalian species without obvious bottleneck history. These results contradict the "species-wide bottleneck hypothesis" of Alpine marmots.