Comparative Analysis And Molecular Phylogeny Of Chinese Deer Based On Mitochondrial 12S RRNA Gene Sequences

This dissertation presents a research on molecular phylogeny of Chinese deer based on complete mitochondrial 12S rRNA gene sequences. Specimens of total 21indivaduls among 14 species of Chinese deer were sequenced, and 16 haplotypes were confirmed by data analysis, then submitted to the GenBank database. (Accession Numbers: AY184425-AY184440).Combined with other several full 12S rRNA sequences of Chinese Water deer, Montijac, Water deer, cow, horse, goat and tragulus retrieved from GenBank database, the whole set of sequences was utilized for downstream analysis based on theories and models in Molecular Phylogeny, whereas the secondary structure of 12S rRNA was predicted and analyzed based on present small subunit of ribosome model. The conclusions are as follows: (1) The topologic structure of phylogenetic tree from both Minimum Evolution and Neighbor Joining methods are generally coincident;(2)Within Cervidae, the distances among intraspecies are less than 1 % (0.1 %-0.42% ), while less than 4% (1.29% -3.44% ) among interspecies within Cervus, compared with 4.65%-8.86% among inter-genus within Cervinae; and the distance between Cervidae and Bovidae is at the range of 11.75%-14.13%. (3) The data support that Roe deer( Capreolus capreolus )moved into Hydropotinae(presently in which there is only one species: Hydropotes intermix) and stemed its own independent genus; (4) The results are object to the usual standpoint that dusky musk deer and alpine musk deer are two different species; (5 ) It is more reasonable that Moschidae (musk deer) is placed at the level of super family; (6) The number of transition within 12S rRNA is within the range of 2 to 20 times bigger than that of transversion; (7) As to nucleotide composition , Adenine (A) is much more abundant than any of other bases (averagely 36.88% ) and guanine (G) is the least (averagely 17.65% ) in the complete sequence, which is similar with the loop region. ( 8 )The substitution rate in loop regions is 2.24 times of that in stem regions. The transition rate is almost same (0.051 and 0.082) , compared with the results that the transversion rate of loop regions is the 12.67 times of that of stem regions. (9) A 12S rRNA secondary structure was predicted based on the sequences in the dissertation.(10) The average evolution rate of 12S rRNA gene is (0.3418%+0.0390% ) /site-MY within 10 million years.