Conservation genetics of freshwater fish

Genetic markers have helped to resolve many difficult taxonomic problems an d map patterns of diversity within and among remnant populations of threate ned and endangered species. Knowledge of historical patterns of gene flow c an help to manage dispersal among anthropogenically fragmented populations. Genetic considerations are used in the design of captive breeding programm es that avoid inbreeding depression and artificial selection that may impac t on Darwinian fitness. Case studies from endangered populations of topminn ows from North American deserts are used to illustrate a variety of methods used in conservation genetic studies. Several merits of studying putativel y neutral, molecular markers v. adaptive phenotypic traits are discussed. ( C) 1998 The Fisheries Society of the British Isles.