Construction of a genetic linkage map and QTL mapping for sex indicate the putative genetic pattern of the F1 hybrid Scylla (Scylla serrata ♀ × S. paramamosain ♂)

Abstract To provide a valuable framework for genome sequence assembly towards the elucidation of the F1 hybrid Scylla (Scylla serrata ♀ × S. paramamosain ♂) genome as well as a reference for QTL mapping and maker-assisted selection, herein F1 hybrid offspring were obtained and used to construct the first genetic linkage map of hybrid Scylla. We presented a sex-averaged genetic linkage map with 49 linkage groups (LGs) covering 5574 SNP markers. The male map consisted of 40 LGs, whereas the female map comprises 22 LGs. The high quality of this genetic linkage map was verified by the low proportion of distorted markers, the strong linkage relationship between adjacent markers on each LG, and the consistent source of the larger segment in each individual. All sex-linked markers distributed in three QTL regions were located on LG12, indicating the chromosome corresponding to LG12 seems to be the sex chromosome of the F1 hybrid offspring. A sex-linked LG comparison of the genetic maps between F1 hybrid offspring and the S. paramamosain suggested the conformation of a ZW/ZZ sex determination system in F1 hybrid offspring. Based on the high quality of this genetic linkage map, we described the putative genetic pattern of F1 hybrid diploid offspring. The putative genetic pattern argues the proposition that a formation of chromosome synapsis among different species might be an initial inducement for the divergence of chromosomal forms.