Fish gene maps and their implications for aquaculture

Abstract

So far, fish maps, merely based on linkage groups of biochemical markers, have to some extent been hindered by lack of all the mapping methodologies currently used in higher vertebrates. In salmonids and xiphophorus species, though, more than 50 and 80 loci have been assigned to 18 and 20 linkage groups, respectively. However, the exploitation of comparative mapping data together with natural fish features as high reproductive capacity, interspecific fertile hybrids and parthenogenesis, and the currently growing array of DNA‐markers and techniques, will speed up the fish map development considerably. We have taken advantage of this by basing our linkage analysis on a material consisting of Atlantic salmon dams and their haploid gynogenetic offspring (female counterpart of sperm typing). Our mapping landmarks are polymorphic microsatellites and genes within the MHC region. Tentative microsatellite based linkage groups have been defined together with a prelimeinary physical map of the MHC region. It is expected that fish maps, in addition to their contribution to understanding the dynamics of genomic flux and evolution, also will have significant impact on important issues like the monitoring of populations and selective breeding.