Fish. 26 March 2008 Conservation Genetics of Freshwater Fish The research of R. C. Vrijenhoek en d Conservation Genetics of Freshwater Fish focus on the utilization of putatively neutral molecular markers in the study of conservation genetics.
Admitting that the use of this particular method is still highly debated among scientists, he stresses its indispensability and efficiency: “Molecular markers have proven their usefulness in solving many difficult taxonomic problems with endangered species, in designing and monitoring captive breeding programs and understanding breeding systems, in detecting geographical structure of genetic diversity, in managing gene flow, and in understanding factors which contributed to fitness” (15).
The research starts with the introduction of how the genes of freshwater fish are altered because of many unavoidable factors which include deforestation, watershed erosion, siltation, agricultural hazards, and recreation. The effects “competitive replacement and genetic swamping of native species” (2) is manifested by the rapid homogenization of freshwater fish fauna which in turn, can alter local fish communities and destabilize aquatic ecosystems.
]Thus, the conservation genetics of freshwater fish becomes important as it allows the resolution of problems among taxonomically difficult groups, design of captive breeding programs, detection of diversity within and among geographical population, management of gene flow, and understanding factors which are essential in the maintenance of the species’ fitness (2).
The research also expounded on the importance of captive breeding for: “conservation and rescue. stocking and supplementation of sport and commercial fishing. domestication and selective breeding of food and ornamental varieties. experimental research organisms. and exhibition and education” (3). However, it is also recognized that as captive breeding involves taking the fish from their natural habitat, conservation genetics needs to create natural breeding system which will give more accurate results to studies conducted.
Lastly, gene flow must be managed in order to efficiently conserve the characteristics of the native species. With this, two models are proposed: the Death Valley Model which reconstructs historical patterns of connectivity among currently isolated pupfish populations and the stream-hierarchy model which looks at the hydro-graphical organization of river systems.
The paper concludes with the importance of molecular markers with regards to the conservation genetics. The case study with the P. monacha highlights that molecular markers are not invariably neutral but can be a great effectors of fitness and that the persistence of molecular polymorphisms can be linked to genetic hitchhiking.
This is true especially to small structured populations of freshwater species. On the other hand, DNA markers should not be taken as neutral which implies that researchers should strive to generate their evolutionary inferences from as many molecular markers as possible in order to come up with a more accurate conclusion. This is crucial as it can indicate the patterns between selective and non-selective processes which can be utilized in the design of genetic conservation programs.
Vrijehoek, R. C. Conservation Genetics of Freshwater Fish.(1998).