R. C. VRIJENHOEK
Center for Theoretical & Applied Genetics, Rutgers University, New Brunswick,
NJ 08903-0231, U.S.A.
Genetic markers have helped to resolve many difficult taxonomic problems and map patterns
of diversity within and among remnant populations of threatened and endangered species.
Knowledge of historical patterns of gene flow can help to manage dispersal among
anthropogenically fragmented populations. Genetic considerations are used in the design of
captive breeding programmes that avoid inbreeding depression and artificial selection that may
impact on Darwinian fitness. Case studies from endangered populations of topminnows from
North American deserts are used to illustrate a variety of methods used in conservation genetic
studies. Several merits of studying putatively neutral, molecular markers v. adaptive
phenotypic traits are discussed. ? 1998 The Fisheries Society of the British Isles
Key words: fish; conservation; genetics; molecular markers; topminnows; Poeciliopsis