Original paper

A preliminary amplified fragment length polymorphism (AFLP) analysis of Spirula spirula (Cephalopoda: Spirulida)

Warnke, Kerstin M.

Abstract

The decabrachian cephalopod Spirula spirula has a worldwide patchy distribution near oceanic islands and the continental shelf in tropical and subtropical waters. The question whether S. spirula from disjunct ranges of the East Atlantic Ocean, that is from South Africa and from Canary Islands-Morocco, are part of the same population, deserves to be investigated. The amplified fragment length polymorphism (AFLP) technique was used for the first time for a decabrachian cephalopod. Using the neighbour-joining method based on Nei and Li's distances of AFLP phenotypes no clear structure could be detected. With the help of a Bayesian assignment using the program Structure the results were congruent. The individual-based clustering failed to reveal significant structuring since the most likely number of clusters after Pritchard et al. (2000) was K = 1. Under the ΔK criterion of Evanno et al. (2005) three clusters were found, but ΔK cannot be measured for K = 1. However, in runs where K = 3, all animals were admixed. In summary, all results supported the existence of a single genetic cluster and therefore probably one population living in eastern Atlantic waters, from Fuerteventura and the coast of Morocco to South Africa. These results remain preliminary, because of the limited number of samples. Yet, the quality of the data was supported by congruent results using different methods.

Keywords

spirula spirulaaflpgenetic clusterstructureneighbour-joining (nj)expected heterozygosity