tailieunhanh - báo cáo khoa học: " The origin of populations of Arabidopsis thaliana in China, based on the chloroplast DNA sequences"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: The origin of populations of Arabidopsis thaliana in China, based on the chloroplast DNA sequences | Yin et al. BMC Plant Biology 2010 10 22 http 1471-2229 10 22 BMC Plant Biology RESEARCH ARTICLE Open Access The origin of populations of Arabidopsis thaliana in China based on the chloroplast DNA sequences Ping Yin1 Juqing Kang1 Fei He1 Li-Jia Qu1 2 Hongya Gu1 2 Abstract Background In the studies incorporating worldwide sampling of A. thaliana populations the samples from East Asia especially from China were very scattered and the studies focused on global patterns of cpDNA genetic variation among accessions of A. thaliana are very few. In this study chloroplast DNA sequence variability was used to infer phylogenetic relationships among Arabidopsis thaliana accessions from around the world with the emphasis on samples from China. Results A data set comprising 77 accessions of A. thaliana including 19 field-collected Chinese accessions together with three related species A. arenosa A. suecica and Olimarabidopsis cabulica as the out-group was compiled. The analysis of the nucleotide sequences showed that the 77 accessions of A. thaliana were partitioned into two major differentiated haplotype classes MDHCs . The estimated divergence time of the two MDHCs was about mya. Forty-nine haplotypes were detected among the 77 accessions which exhibited nucleotide diversity n of . The Chinese populations along the Yangtze River were characterized by five haplotypes and the two accessions collected from the middle range of the Altai Mountains in China shared six specific variable sites. Conclusions The dimorphism in the chloroplast DNA could be due to founder effects during late Pleistocene glaciations and interglacial periods although introgression cannot be ruled out. The Chinese populations along the Yangtze River may have dispersed eastwards to their present-day locations from the Himalayas. These populations originated from a common ancestor and a rapid demographic expansion began approximately 90 000 years ago. Two accessions collected .