【Animal Modeling】-Analysis of single nucleotide polymorphisms and alternative splicing before and after freezing blastocysts of bovine cattle based on RNA-Seq technology

  Objective To compare and analyze the single nucleotide polymorphisms and alternative splicing of bovine blastocysts before and after vitrification.

  Methods The sperm of common Jersey cattle and yak oocytes were used to obtain bovine calf blastocysts by in vitro fertilization (IVF). The total RNA of the fresh blastocysts and the frozen-thawed blastocysts recovered by vitrification were extracted, and the library was constructed and subjected to high-throughput sequencing. Using SAMtools-0.1.19 and

  ASprofile software performs SNP and AS analysis respectively.

  RESULTS: The fresh blastocyst and frozen-thawed blastocyst samples of bovine bred bovine obtained 51 099 116 and 54 192 358 pieces of data to be analyzed (Clean Reads) after removing low-quality sequences and linking contamination, respectively. Fresh blastocysts and frozen-thawed blastocysts detected 116,681 and 224,750 SNP sites, respectively. In the fresh blastocyst transition type SNP, the number of C/T type is slightly more than that of A/G type; but in frozen-thawed blastocyst, the number of A/G type is slightly more than C/T type; in the two-sample transversion type SNP , the proportion of AT is the least. The ratios of transition and transversion SNPs in fresh blastocysts and frozen-thawed blastocysts were 2.57 and 2.45, respectively. 49 388 and 65 241 AS events were detected in fresh blastocysts and frozen-thawed blastocysts, respectively. There were mainly 5 types of AS, among which the transcription initiation region and transcription end region accounted for the largest proportion.

  Conclusion Using RNA-Seq technology to compare and analyze the SNP and AS of bovine blastocyst before and after vitrification, it can provide effective data and theoretical basis for the subsequent analysis and mining of related gene functions before and after freezing of human embryos.