| Based on omics technology and high-throughput sequencing technology,this study analyzed the transcription and expression of early embryonic genes in sheep at different stages from a single embryo level,and studied the embryonic development characteristics of mulberry and blastocyst stages,and then studied the possible factors related to rapid embryonic development and embryonic cell differentiation.To provide theoretical basis and data support for further study of early embryonic life activities.1.By analyzing the gene expression characteristics of morula and blastocyst in sheep,a total of 15689 differentially expressed genes were screened,with 484 significantly up-regulated genes and 326 significantly down-regulated genes.Through GO functional enrichment analysis,the genes enriched in the BP and CC regions were significantly more than those in the MF region.In the MF classification,up-regulated and down-regulated differential genes were mainly enriched in intercellular connection and regulation of catalytic activity.In the BP and CC classification,they were mainly enriched in the development process and structural composition of cells and organelles.Mulberry embryos and blastocysts still have some stem cell characteristics,showing rapid proliferation characteristics.The results of KEGG pathway enrichment analysis showed that gene expression regulation was mainly regulated by embryonic cell proliferation,metabolism and expression after genome activation.Embryonic cells and cancer cells have similar characteristics,mainly enriched in metabolic and rapid proliferation-related pathways.Mulberry embryos to blastocyst stage have shown the characteristics of functional differentiation,and the decrease of omnipotency is an important stage of embryo differentiation.2.During the development of sheep morula and blastocyst,CDK1,CDK2,CDK4,CDK6,MAD2L1,MAPK12,BMP2,BMP4,GATA3,TRA2 B are involved in the regulation of embryonic proliferation and differentiation,and play an important role.Further quantitative expression results in morula and blastocyst showed that CDK1 and CDK4 were up-regulated and the difference was significant.The expression differences of CDK2,CDK6 and MAPK12 were not significant.MAD2L1 expression was low and the difference was not significant.The relative expression of BMP2 and BMP4 genes showed that the expression of BMP4 was significantly up-regulated,and the difference of BMP2 expression was not significant,which was consistent with the embryonic development process.GATA3 was expressed in both morula and blastocyst,and the difference in relative expression was not significant and stable.The quantitative results of TRA2 B relative expression showed that the difference was not significant,which may be involved in the regulation of embryonic proliferation,differentiation and development,and further research is needed.3.In order to further study the gene transcription and expression characteristics of different sex embryos,the sex of sheep embryos was identified by DNA level and the identification effect was optimized.SRY gene was amplified by ultramicro DNA using embryo cutting technology.The sensitivity of the system for the identification of sheep embryo gender was about 10 pg(3 ～ 4 cells),and the system was stable and effective..In conclusion,early embryonic development is regulated by strict and accurate multi-signal pathways to ensure the normal development of embryos.The proliferation and differentiation of embryonic cells is one of the key factors for embryonic development.Gene transcription with different functions promotes the process of division and differentiation.It is generally believed that the first lineage of embryonic cells differentiates in blastocyst stage during a series of changes,but may actually be earlier.The optimized method for sex determination of sheep early embryos at DNA level is better,but it is still difficult to identify the sex of sheep early embryos before transcriptome sequencing. |
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