Research On The Hoxc8 And Hoxd11 Methylation And Mutation In Sheep

The Hoxc8 and Hoxd11 for Mongolian, Dorset, German Merino, and Australia Merino sheep were sequenced. The positions, the numbers, the stability and the transformation ability from parents to offspring of methylated cytosine were confirmed by BSP. The differences of the methylation between male and female in the same generation, between the haploid (sperms) and diploids (blood cells), the functions and mechanism of the methylation, including the relationship between the methylation and the variations of the numbers of the thoracic vertebrae and the probability of application in the breeding were discussed separately.There were 2108 bases in the Hoxc8 gene sequence, including 436 bp for the exon-1, 293 bp for the exon-2 and 1378 bp for the intron in sheep genome (GenBank Accession No.GU479925). There were 35 CpGs, and C+G was 61.01% in the exon-1. The 2 CpGs located first and second base in the genetic codes coding arginine. 13 CpGs located second and third base in the genetic codes, 20 CpGs located the third base of last codon and the first base of next codon. There were 12 CpGs in the exon-2.There were 1776 bases in the Hoxd11 gene sequence, including 778 bp for the exon-1, 236 bp for the exon-2 and 762 bp for the intron in sheep genome (GenBank Accession No.GU059862). There were 120 CpGs, and C+G was 76.74% in the exon-1. The 8 of the 120 CpGs located first and second base in the genetic codes, and all the 8 CpGs coding arginine. 47 CpGs located second and third base in the genetic codes, 65 CpGs located the third base of last codon and the first base of next codon. There were 12 CpGs in the exon-2. This high density of CpG in the exon-1 for Hoxc8 and Hoxd11 might be meaning the major part of the cytosine methylation occurred regionFor Hoxc8 and Hoxd11 in German Merino, Dorset, Australia Merino, there were some differences from that of Mongolia sheep. 5 mutations (a C inserted at 494 b, C→T at 1120 b, T→C at 1528 b, A→G at 1922 b, A→G at 2063 b) in Hoxc8 and 3 mutations (C→T at 471 b, C→A at 693 b, G→A at 1034 b) in Hoxd11 for Mongolia sheep were found. In the 3 foreign breeds, only one mutation(T→C at 1528 b)was found in Hoxc8, but no mutation found in Hox d11.The results of BSP for Hoxc8 exon-1 indicated that the CpGs methylation rate was related to the numbers of the thoracic vertebrae. And the relationship were only worked for pure breed Mongolia sheep, but do not worked for foreign sheep and cross breed. The methylation rate of the diploids was higher than the gamete.The functions of the exon methylation in the transcription and translation were related to the changes of the quantum mechanics of the sequences resulted from DNA methylation.