The present study was designed to investigate the phenomenon of color polymorphism in the genetic structure of the African snail species Archachatina marginata from Akwa Ibom, Cross River, and Rivers States in Nigeria. For this purpose, 48 adult snails were collected and analyzed, including 24 from each ecotype: 24 black-skinned (BS) and 24 white-skinned (WS), with 16 from each state. Genetic diversity was evaluated using mitochondrial cytochrome b and Single Nucleotide Polymorphism (SNP) markers. WS ecotypes were found to have formed a cohesive group with minimal genetic divergence (0. 04-0. 10), suggesting recent maternal ancestry and high gene flow. On the other hand, BS ecotypes were found to have high genetic diversity with certain lineages (CYT₁2 and CYT₁5) showing deep divergence (0. 45-0. 63). Genetic divergence between WS and BS ecotypes was found to be moderate (0. 470). Phylogenetic tree results showed that the mitochondrial DNA formed three major clusters with mixed color morphs. Haplotype diversity was found to be high in both ecotypes: BS (1. 000) and WS (0. 968), while nucleotide diversity was found to be moderate. These findings suggest that colour polymorphism in A. marginata snails is actually a phenotypic variation in a genetically linked population rather than genetic ecotypes. However, the limitations of the study include the low number of samples and the use of only mitochondrial markers. Future studies should include a larger population and geographic distribution of the samples and use nuclear markers to reveal the genetic basis and evolutionary implications of colour polymorphism in A. marginata snails.
Etukudo et al. (Sat,) studied this question.