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Ghrelin is an important peptide that stimulates food intake and regulates energy balance of animals. Single nucleotide polymorphisms of ghrelin gene in three Chinese cattle populations were investigated through PCR-SSCP and DNA sequencing. Five over-lapped DNA fragments were analyzed and a total of three ones exhibited different genotypes. Three genotypes and four SNPs (-415 A > G, -414 T > C, -321 C > A, and -172 A > G) were found on the -544 to +35 bp region (G-1) of ghrelin gene. On the locus of -1037 to -509 bp (G-2), two genotypes and one SNP (-726 A > T) were discovered. And in the exon1, exon2, and intron1 (G-4 locus, (+4 to +427)), two genotypes and one SNP were detected (+205 C > T, located in intron1). Positions of the five SNPs in the 5′ regulatory region might be the transcription factor binding sites. The SNPs at -415 and -414 in the core binding sequence were found to cause the change of the site. Though the SNP at -172 did not change the binding site, it generated one new site at the same time. The frequencies of the genotypes varied differently in the three breeds. Results of ANOVA showed that G-1 was correlative to the ischium width (IW) of Nanyang cattle aged 18 months (p = 0.043). The least square analysis between genotypes at G-1 locus and growth traits in Nanyang cattle showed that the individuals (aged 18 months) with C genotype had greater IW than that of the other two genotypes. The C genotype might serve as one potential candidate genetic marker for cattle growth and development.

The aim of the present study was to identify and characterize polymorphisms within the coding region and the 3' flanking region of the bovine serotonin receptor 1B gene among different cattle breeds. Four DNA fragments were amplified by polymerase chain reaction and then used for polymorphism identification by SSCP. The fragments showing different SSCP patterns were sequenced. And a total of six SNPs (G205T, C507T, C546G, C744T, G816A and G942A) were detected. The SNPs were at Hardy-Weinberg equilibrium except C507T and C546G in all genetic population. The frequencies of allele 205T of Holstein were much higher than that of the other six beef cattle populations. Almost the PIC of all SNPs were not more than 0.10 except that of G205T in Holstein cows, which indicated the bovine HTR1B gene was conserved.

Abstract: Neuropeptide Y (NPY) is one of the most potent orexigenic factors that is implicated in the control of feeding behavior and energy homeostasis. Four Chinese indigenous cattle breeds (n =338) were used to detect single nucleotide polymorphisms (SNPs) in the coding regions with their intron–exon boundaries and the proximal flanking regions of NPY gene by PCR–SSCP and DNA sequencing. Five novel SNPs (38017 C>G, 34240 C>A, 34168 G>A, 32463 A>C and 32302 C>G) were identified. Polymorphisms of P3 lous in NPY gene, containing SNP4 and SNP5, were associated with body length and chest girth in Nanyang cattle aged 6, 12 and 18months (P <0.05), but they had no significant effect on the two growth traits in Nanyang cattle aged 24months (P >0.05). The results open a new field of study and extend the spectrum of genetic variation of the bovine NPY gene, which might contribute to cattle genetic resources and breeding. [ABSTRACT FROM AUTHOR]