Black Line The Hamster Mtnr1a Cloning And Population Genetic Polymorphism Analysis

Cricetulus barabensis is widely distributed in China, and its plays an important role in keeping ecosystem balance. Cricetulus barabensis is one of the deleterious rodents for agriculture and grassland. In this experiment we have studied it at molecular level.Genetic diversity is one of important factors affecting species vitality and reproduction, and is the variation of genetic material which is nucleic acid. Genetic diversity plays a very important role in survival and adaptability of a species. The richer genetic variation of a species (population) is, the stronger its adaptation to the external environment is. On the contrary, the adaptation is weaker. Single nucleotide polymorphism (SNP) which has been considered as the third genetic marker for molecular research is widely used in the genetic relationship, genetic map construction, analysis of genetic diversity. The use of molecular markers, revealing polymorphism at the DNA level, has been playing an increasing part in genetics studies. The new marker type (SNP) is now on the scene and has gained high popularity.Melatonin elicits its biological effects through high affinity G protein-coupled receptors that are responsible for melatonin to effect on mammalian circadian rhythm, regulation of retinal signals and reproductive seasonality affected by day length and son on. In the past, the study about melatonin receptor 1a in Cricetulus barabensis has never been reported at home and abroad. In order to study biological information about genetic diversity of different populations, genetic relationship within species and so on, the author has analyzed the single nucleotide variation of different populations which could provide the theoretical basis for genetic diversity and genetic structure.First of all, the author designed two primers with the software:Primer5.0, Oligo6.0 and MTNR1A gene sequences of Cricetulus barabensis related species:Mesocricetus auratus and Phodopus sungorus which have been registered in GenBank. Second, the gene fragments were amplified from three populations in Yinan, Linqu and Qufu areas, Shandong province, China, then cloned and sequenced. The 232 gene fragments are the 5'UTR and exon 1 sequence and partial exon 2 sequence. This experiment mainly analyzed the single nucleotide polymorphisms (SNPs) in three different populations of Cricetulus barabensis, and the comparison of polymorphism among Cricetulus barabensis by use of Chromas, ClustalX, DNAman, DnaSP5.0, MEGA3.1 and other key sequence analysis software in order to explore the reason for the variation in different geography populations of Cricetulus barabensis and the variation level among different subspecies.The major results were as follows:(1)The 232 partial sequences (1708 bp) were amplified with PCR and the fragments contained the 5'UTR (725 bp) sequence and exon 1 sequence (185 bp) and partial exon 2 sequence (798 bp). There are 19 polymorphic loci and 55 haplotypes (HM099922～HM099976) of the 5'UTR and exon 1 sequence and 13 polymorphic loci and 18 haplotypes (HM099977～HM099994) of partial exon 2 sequence.(2) There were 4 kind of regulatory sequence in the 5'UTR of MTNR1A:CAC, GAGA, GC_SP1, GC and little transcriptional start site:AT and TA. However, the author did not find the typical TATA box and CAAT box in 5'UTR.(3) The bases mutation (290,292,325,716,940) lead to amino acid change (N77S, L78M, L109V, F239S and V314I) by comparison between Spring and Autumn population. The importance thing is that the amino acid change (N77S, F239S, V314I) only appear in Autumn population, and the amino acid change (L78M, L109V) only appear in Spring population, so the author concluded that it has relation to season. Transversion, insertion and conversion from 251 to 253 not only lead to amino acid change, but also change the coding order. The three bases change had no relation to season.(4) There was divergence of genetic diversity in three populations and the Linqu population genetic diversity is greatest, the Qufu population genetic diversity is greater than the Yinan population genetic diversity.(5) This result demonstrated that the differentiation of three populations was unconspicuous. The NJ phylogenetic tree also indicated the same result.