Nonlethal genetic study of freshwater mussels using randomly amplified Polymorphic DNA (RAPD) analysis.

Abstract

Freshwatermussels (Bivalvia:Unionidae)represent a diversegroup of benthic macroinvertebrates that dominate faunal components of streams, rivers and lakes. Unable to avoid the cumulative effects of pollution, pesticides and heavy metals, many species face range reductions and potential extirpation from the state. In this study a nonlethal DNA isolation technique was developed for use with freshwater mussels. Genetic analysis was performed using Randomly Amplified Polymorphic DNA (RAPD) and dendrogram profiling. Three random primers designated 1050, 1070 and 1283 were used to study genetic diversity between 3 species of mussels from the Neosho and Verdigris Rivers. All 3 primers detected differences between river drainages and species as well as diversity within species. Band pattern analysis following amplification from 82 mussels using primer 1050 and 1070 generated 11 different sized bands, whereas primer 1283 revealed 17 different sized bands. Dendrogram profiles revealed 24 groupings for primer 1050,21 groupings for primer 1070, and 24 groupings for primer 1283. Dendrogram profiles using all 3 primers to test for differences within species and between river drainages using primer 1050 revealed 6 unique biotypes in the Verdigris River and 2 in the Neosho River for Quadrula quadrula. Repeating this with primer 1070 revealed 10 unique biotypes in the Neosho River and only 4 unique to the Verdigris River for Quadrula pustulosa. Dendrogram profiles using primer 1283 revealed 11 different groupings for Quadrula pustulosa, with 7 unique biotypes in the Neosho River and only 1 unique to the Verdigris River, supporting the idea that the Neosho River has more diversity. A mark and recapture study was also done to confirm survivability following the tissue biopsy. Overall recapture efforts resulted in a 65% total recovery, with 56% coming from the Neosho River and a 78% from the Verdigris River. Quadrula metanevra made up the largest percentage of mussels recovered from the Neosho River, constituting 63%, while Quadrula quadrula and Quadrula pustulosa made up 55% and 45% respectively. Recovery results from the Verdigris River revealed Quadrula quadrula had the highest recovery rate with 80%, while Quadrula pustulosa made up 71%. The overall ability of RAPD analysis in this study to discern unique biotypes, combined with the nonlethal tissue biopsy proved to be a successful method for performing genetic analysis on freshwater mussels.