A Comprehensive Roadmap Of Dairy Goat Spermatogenesis Defined By Single-cell RNA-seq

The Guanzhong dairy goat is a dairy breed that combines the advantages of the Xinong Saneng dairy goat and the local goats in the Guanzhong area of Shaanxi.Its reproductive rate is high,and its milk performance is good.Dairy goats are an important component of the animal husbandry industry.But due to the lack of improved breeds and low reproductive rates,this has been hindering the rapid and healthy development of the dairy goat industry.How to efficiently select high-quality breeding animals is a difficult problem and one of the concerns of people.Exploring the spermatogenesis process and accurately defining the spermatogoniaspecific marker genes of dairy goats has important guiding significance for better selection and breeding.Spermatogenesis is a complex and continuous process.Due to this characteristic,there are usually 3 to 4 waves of spermatogenic waves in the seminiferous epithelium of the testis that include all stages of spermatogenic cells.This heterogeneity of the testis has caused great distress to scholars who study the process of spermatogenesis.The emergence and development of single cell RNA sequencing(sc RNAseq)has solved the problem of cell heterogeneity in mammalian tissue or organogenesis.This study systematically defined the spermatogenesis process of dairy goats through single-cell sequencing technology,identified five basic spermatogenic cell clusters.The specific research results are as follows:(1)The single cell transcriptional atlas during the spermatogenesis stage and somatic cells of Guanzhong dairy goats were successfully identified at single-cell resolution.Based on t SNE clustering analysis,the spermatogonia,early spermatocytes,late spermatocytes,round spermatids and elongated spermatids in the spermatogenesis of Guanzhong dairy goats were successfully identified.And described the gene expression profiles of these types of cells.By the analysis of differences between different cell types,several marker molecules with celltype specificity were identified.Based on the Monocle analysis,the pseudotime differentiation trajectores of germ cell lines,Sertoli cells,Leydig cells and myoid cells were successfully constructed.The dynamic analysis of spermatogenesis was carried out,and the change process of pseudotime gene expression during spermatogenesis in Guanzhong dairy goats was described.(2)Screened and identified the specific expression genes of Guanzhong dairy goat spermatogonial cells: TKTL1 and AES,and verified the expression of TKTL1 and AES in sheep data.In summary,this study used sc RNAseq sequencing technology to analyze the spermatogenesis process of Guanzhong dairy goats for the first time.The main cell types were identified at the single-cell level,and the gene expression profiles of different types of cells involved in the spermatogenesis of Guanzhong dairy goats were elaborated for the first time.The changes in gene expression during spermatogenesis were described,and the somatic cell development of Guanzhong dairy goats during adolescence was revealed.The results of this study enriched people’s understanding of the spermatogenesis of Guanzhong dairy goats,and provided strong theoretical and technical support for Guanzhong dairy goat breeding research.