Abstract:Genetic linkage map of Portunus trituberculatus was constructed using “double pseudo testcross” strategy with AFLP and SSR molecular labeling techniques. In this study, maternal and paternal broodstock were sampled from Laizhou Bay and Zhoushan Island wild populations of P. trituberculatus, respectively. Through the directional mating (1♂×3♀), the wild parents were used to generate F1 family. The 108 progenies of directional mating F2 family coming from sisterhood intercross between F1 family and its parents were used as experiment materials. Sixty AFLP primer combinations and 3 pairs of SSR primers were screened to produce 214 maternal markers and 195 paternal markers. There were 155 markers which included 153 AFLP markers and 2 SSR markers segregating as 1∶1 model from 214 maternal markers. 139 markers which contained 138 AFLP markers and 1 SSR marker segregated in 1∶1 model in 195 parental markers. The female linkage map consisted of 100 markers distributed in 9 linkage groups (more than three markers), 6 triplets and 15 doublets, which covered a total length of 1 544 cM. Average marker spacing of female linkage map was 22.0 cM and the observed genome length accounted for 52.9% of the estimated genome length. The paternal linkage map consisted of 71 markers distributed in 6 linkage groups, 6 triplets and 11 doublets, spanning the distance about 1 174.2 cM with average marker spacing of 24.0 cM and its genome coverage was 49.5%. The Pearson analysis results showed that all the genetic markers distributed in linkage map uniformly. This study provided a starting point for further construction of high density linkage maps, as well as for the mapping of functional genes and the location of quantitative trait loci (QTL) in P. trituberculatus.
