Identification And Analysis Of Sex Chromosomes Of Birds And Chinese Soft-shelled Turtle

Sex chromosomes play an extremely critical role in species with genotypic sex determination,but people still know little about the origin and evolution of sex chromosomes.For a long time,due to the high degree of specialization of sex chromosomes,only the complete chromosome sequences of a few species have been published.With the rapid development of sequencing technology,this situation has been greatly improved.In this project,birds and Chinese soft-shelled turtle,species with ZW sex chromosome system were selected as the research objects.Based on large-scale bird genomes,ZW sequences and pseudoautosomal region of more than200 bird species were identified through calculation of sequencing depth and alignment with reference genomes.At the same time,the DNA of Chinese soft-shelled turtle was sequenced through a variety of sequencing technologies.Based on the sequencing data,the assembly of the third-generation high-quality genome of Chinese soft-shelled turtle and the identification of sex chromosomes were completed.In addition,we collected embryonic tissues of Chinese soft-shelled turtle at different developmental stages,then extracted RNA and completed RNA sequencing.Through hierarchical cluster analysis of gene expression between different samples,we preliminarily infer that the Chinese soft-shelled turtle begins sexual differentiation during stage 15-16 of embryonic development.This project has laid a good foundation for further research on the evolution of bird sex chromosomes and the sex determination mechanism of Chinese soft-shelled turtle.