Microsatellite-based consensus map of the Pacific oyster (Crassostrea gigas)

Linkage map is basic prerequisites for marker-assisted selection and map-based cloning. However, the number of co-dominant genetic markers on linkage maps published for the Pacific oyster (Crassostrea gigas) is still low. Microsatellite markers are inherited as co-dominant, which are reproducible and high polymorphism. They are easily transferred among populations and laboratories, and one of ideal joining markers to construct a consensus map. In order to improve the number of microsatellite markers, a consensus map of C. gigas was constructed based on common microsatellite markers among six mapping populations. The consensus map contained 161 microsatellite markers, spanning 10 linkage groups. The map length and average genetic distance is respectively 615.4 cM and 3.8 cM. The number of loci on linkage group ranged from 10 to 24 and the genetic length of linkage group varied from 47.3 to 73.3 cM. At present, this consensus map is the densest SSR-based map of C. gigas. Among different mapping populations, the grouping of markers is consistent; however, the order of markers is a little different, which likely attributed to polymorphism for chromosomal rearrangements in the natural population of Pacific oysters. The consensus map will provide a new reference tool for genetics and breeding of C. gigas in the future.