Geographic structuring of molecular and morphological polymorphism in Pyrenean populations of the snail Cepaea nemoralis

✍ Scribed by D. Caugant; R. K. Selander; J. S. Jones

• Publisher: Springer Netherlands
• Year: 1982
• Tongue: English
• Weight: 947 KB
• Volume: 57
• Category: Article
• ISSN: 0016-6707
• DOI: 10.1007/bf00056481

✦ Synopsis

To determine whether geographic patterns of variation in the frequency of shell polymorphisms in the land snail Cepaea nemoralis mark regions of extensive genetic differentiation, allele frequencies at six polymorphic enzyme-encoding loci were analyzed electrophoretically in 74 samples from the central part of the Spanish Pyrenees. Within a large 'area effect' for unhanded shells on the southern slope of the Pyrenees, there is no enzyme locus at which allele frequencies are homogeneous. Because this morphological area effect does not mark a region of pervasive genetic change, the genetic structure of populations in the region studied does not conform to recent models of'area effect speciation'. Factor analysis of allele frequencies at three loci controlling shell polymorphisms and six enzyme loci separated populations on the southern slope into two groups, one of which is similar to the group of populations on the northern slope. There is therefore considerable geographic structuring of both molecular and morphological polymorphism in this species.