摘要
试验旨在检测绵羊瘦素受体(leptin receptor,LEPR)基因序列突变位点,为进一步分析LEPR基因多态性与绵羊生长性状的关系奠定基础。选用美利奴羊与阿华西羊杂交群体作为试验材料,利用RT-PCR、测序等方法测定了4只绵羊的LEPR基因cDNA部分序列及内含子7序列,同时利用PCR-RFLP分析两个位点在群体(229只)中的多态性。测定出LEPR基因cDNA序列长2608bp(包含外显子2-16完整序列及外显子1和17的部分序列)和LEPR第7内含子序列全长160bp,共发现5个核苷酸变异位点,第2外显子中2个(T240C和A279G),第10、14外显子中各1个(A1683G,T2373C),内含子7中1个(1285+A73G),外显子中的4个变异位点均未引起编码氨基酸的改变。在研究群体中,A279G与A1683G中A的频率分别为0.415、0.467,后者处于非平衡状态,GG和AA是主要的单倍型。不同物种间序列一致性分值均比较高,但LEPRmRNA区序列一致性比内含子高,基于LEPR mRNA序列构建的系统发育树更符合实际情况,且可靠性值更高。结果表明,绵羊LEPR基因的保守性较强,突变形式主要是转换,A279G和A1683G可能是突变热点。
In order to lay the foundation for further study on relationship between polymorphisms of LEPR and growth traits in sheep,using DNA and RNA samples from a population crossed between Merrino and Awassi sheep,parts of ovine LEPR cDNA and intron 7 were sequenced in 4 ewes in an attempt to find polymorphisms,and DNA from 229 samples were genotyped by PCR-RFLP at two mutation loci.The 2608 bp of LEPR cDNA included complete exon 2 to exon 16 and partial sequence of exon 1 and exon 17,and the whole length of LEPR intron 7 was 160 bp.5 point mutations were found,two in exon 2（T240C and A279G）,A1683G and T2373C were in exon 10 and exon 14 respectively,at the same time,a A to G mutation was found in intron 7（1285＋A73G）.They all didn＇t cause amino acid substitution.Frequencies for allele A at A279G and A1683G were 0.415 and 0.467,respectively.However,the latter was in Hardy-Weinberg disequilibrium,and GG and AA were the main haplotypes in this sheep population.The similarity scores of LEPR cDNA or intron 7 were high among species,though the former were higher,and the phylogenetic tree based on LEPR mRNA was more accurate with higher reliability value than based on LEPR intron 7,which may be caused mainly by the length of intron 7.These results indicated that ovine LEPR was highly conserved,and transition was the main mutation way,in addition,A279G and A1683G were mutational hotspots in LEPR gene.
出处
《中国畜牧兽医》
CAS
北大核心
2011年第8期107-113,共7页
China Animal Husbandry & Veterinary Medicine
基金
四川省教育厅重点项目(08ZA077)
四川省科技支撑计划(2011NZ0003)
关键词
绵羊
瘦素受体基因
单核苷酸多态性
系统发育
sheep
leptin receptor gene（LEPR）
single nucleotide polymorphism（SNP）
phylogenesis
