Recently, important progress in study on mechanism of epigenetic regulation of fish sex reversal was made by Yellow Sea Fisheries Research Institute (YSFRI), Chinese Academy of Fishery Sciences scientists, in cooperation with BGI-Shenzhen. The important findings were published in Genome Research (IF=14.4，2014.24: 604-615) (http://genome.cshlp.org/content/24/4/604.short). This is another major achievement besides the paper on half-smooth tongue soleCynoglossus semilaevis, published in Nature Genetics. Dr. Shao CW from YSFRI and Mr. Li QY from BGI-Shenzhen were co-first authors, and Prof. Chen SL from YSFRI and Dr. Zhang GJ from BGI-Shenzhen were co-corresponding authors.

In recent years, Prof. Chen SL and colleagues from YSFRI completed consecutively the drawing of full genome map and the construction of high density genetic linkage map ofC. semilaevis. On the basis of these work, the team has targeted at the great discrepancy between male and female growth, and the enormous difference in the sex ratio ofC. semilaevisin aquaculture production, and has completed the whole genome DNA methylation sequencing of normal male (ZZ♂), pseudo male (p-ZW♂), normal female (p-ZW♀), and the gonad of F1 pseudo male (f-ZW♂) and female (f-ZW♀) produced by cross breeding of pseudo male and normal femaleC. semilaevis. Whole genome methylation profiles of single base resolution were drawn.

It was found that the sex reversal ofC. semilaeviswas accompanied by sex determination and status changes in differentiation pathway related gene methylation. Additionally, the mechanism of dosage compensation for sex chromosome gene expression after the sex reversal was analyzed. It was revealed thatC. semilaevispseudo male lacks an overall dosage compensation for sex chromosome, but there was a partial dose compensation area; at the same time, F1 pseudo male has inherited the male parent’s methylation mode. This is the first time that transgenerational inheritance of sex reversal in fish was discovered. This research result has provided a basis for the tendency of sex reversal in the offspring ofC. semilaevispseudo male, and offers a new thought for analyzing the mechanism for sex reversal in fish, and gives us a new approach for sex control and high-female breeding ofC. semilaevis.

The work was supported by the National Natural Science Foundation of China, National High-Tech Research and Development Program of China (863 Program), and Public Welfare Industry (Agriculture) Special Program.