The mud crab ( Scylla paramamosain ) is a traditional marine fishery resource and mariculture crab species in China. It plays an important role in China’s marine economic industry. There are significant differences between female and male crab, not only in morphological characteristics, nutritional value and market price, but also in genome and transcriptome.
We carried out a systematic study on the sex determination and differentiation of the mud crab, in order to reveal the differences between genders and the genetic mechanism of sex determination and differentiation. The phenotypic differences between male and female in the early stage were clarified by microscopic observation, which laid a foundation for the study of gender differentiation. The whole genome of mud crab was sequenced, and the chromosome level genome map was drawn (Figure 1). Thirteen female- specific SNP markers (female heterozygous and male homozygous) were identified , and a molecular technique for rapid identification of genetic sex was established. High-density genetic maps were constructed with the first- generation and second-generation families of S. paramamosain as the mapping populations, which located the sex determining region and sex-specific SNP markers . At the same time, another genetic map was constructed with the hybrid F1 generation of hybrid family (S. serrata ♀ × S. paramamosain ♂), which also located the sex determining region. The above findings suggest a ZZ/ZW chromosome sex determination system in the mud crab, and they could be helpful for better understanding the sex determination and differentiation mechanism of crabs.