Biotemas (Mar 2010)
Method of obtaining metaphase cells for oyster karyotyping
Abstract
Currently, mariculture is growing on the coast of Santa Catarina and Florianópolis is the largest producer of oysters in Brazil, cultivating the Japanese oyster Crassostrea gigas (Thunberg, 1793). Regarding the native oyster, many types of study are needed, including those that help to elucidate the complex question of the number of species of the genus Crassostrea. Taxonomic studies of oysters have been based almost exclusively on the morphology of the shells of recent and fossil individuals, and they have not always been effective in differentiating between species. Cytogenetic information can be important, to provide additional features to aid in taxonomy. The aim of this study was to test and adapt methodologies traditionally applied in animal cytogenetics to obtain metaphase cells for oyster karyotyping. Specimens collected in Ponta do Sambaqui – Florianópolis/SC/Brazil. Were used the most effective method was obtained using gills from animals treated for 12h in a solution of 0.005% colchicine in seawater, plus treatment with hypotonic solution for 30min with deionized water 1:1. This paper presents a method to obtain a greater number of metaphases, with few overlapping chromosomes and well-defined chromosome morphology.
