Qualitative and quantitative methods show stability in patterns of shell polymorphism in the Pyrenees over five decades.

Over the past century, the study of animal color has been critical in establishing some of the founding principles of biology, especially in genetics and evolution. In this regard, one of the emerging strengths of working with the land snail genus is that historical collections can be compared against modern-day samples, for instance, to understand the impact of changing climate and habitat upon shell morph frequencies. However, one potential limitation is that prior studies scored shell ground color by eye into three discrete colours yellow, pink, or brown.

Recombination within the Cepaea nemoralis supergene is confounded by incomplete penetrance and epistasis.

Although the land snail Cepaea nemoralis is one of the most thoroughly investigated colour polymorphic species, there have been few recent studies on the inheritance of the shell traits. Previously, it has been shown that the shell polymorphism is controlled by a series of nine or more loci, of which five make a single 'supergene' containing tightly linked colour and banding loci and more loosely linked pigmentation, spread band and punctate loci. However, one limitation of earlier work was that putative instances of recombination between loci within the supergene were not easily verified.