中文摘要：

本研究旨在了解褪黑激素受体基因MTNR1B的多态性及其与文昌鸡产蛋性状的关系。用直接测序的方法检测MTNR1B5′调控区、外显子1和外显子2的单核苷酸多态性,并将其与文昌鸡的产蛋性状进行关联分析。结果表明,在外显子1和2的编码区未发现碱基突变或缺失,而在5′调控区发现15个单核苷酸多态位点。其中-778位点突变（A→G）对文昌鸡中期（22～31周龄）产蛋数和46周龄总产蛋数的显性效应分别达到了2.3和6.2枚（P〈0.05）。对后期（32～46周龄）产蛋数和46周龄总产蛋数而言,-216位点C对A为优势等位基因,加性效应值分别为2.5和3.2枚,显性效应分别为3.5和6.8枚,且表现为超显性。在4种单倍型中,AA单倍型个体的后期产蛋数和46周龄总产蛋数最低,GC单倍型个体的开产日龄最早。AC/GA联合基因型母鸡拥有最高的中期产蛋数、后期产蛋数和46周龄总产蛋数。综上所述,MTNR1B基因的外显子高度保守,而5′调控区的SNPs有望成为影响产蛋性状潜在的遗传标记。

英文摘要：

The objective of this study was to investigate the polymorphism of the melatonin receptor gene（MTNR1B） and its association with laying traits in Wenchang chickens.Single nucleotide polymorphisms（SNPs） were detected in 5′ regulatory region,exon 1 and exon 2 of MTNR1B by direct sequencing,and the association of SNPs with laying traits was also analyzed.The results showed that no base mutations or deletions were detected in exon 1 and exon 2,while 15 SNP loci were found in 5′ regulatory region.Dominance effects at-778 locus were 2.3 and 6.2 eggs for egg number from 22-to 31-week-old and total egg number until 46-week-old,respectively.At-216 locus For egg number from 32-to 46-week-old and total egg number until 46-week-old,additive effects were 2.5 and 3.2 eggs,respectively,and dominance effects were 3.5 and 6.8 eggs,respectively.Hens with the haplotype AA had the least egg number from 32-to 46-week-old and egg number until 46-week-old and hens with the haplotype GC had the earliest age at first laying.Hens with combined genotype AC/GA had the most egg number during the periods from 22-to 31-week-old,32-to 46-week-old.In conclusion,exons of MTNR1B are highly conservative,while SNPs in 5′ regulatory region are maybe as candidate markers for laying traits.