Mitochondrial genome sequences of Artemia tibetiana and Artemia urmiana:assessing molecular changes for high plateau adaptation  

作　　者：ZHANG HangXiao LUO QiBin SUN Jing LIU Fei WU Gang YU Jun WANG WeiWei 

机构地区：[1]CAS Key Laboratory of Genome Sciences and Information,Beijing Institute of Genomics,Chinese Academy of Sciences [2]University of Chinese Academy of Sciences [3]Department of Genome Oriented Bioinformatics,Technische Universit t München,Wissenschaftszentrum Weihenstephan,Freising 85350,Germany [4]Division of Gastroenterology,Department of Medicine,University of Alberta,Edmonton T6G 2V2,Alberta,Canada

出　　处：《Science China(Life Sciences)》2013年第5期440-452,共13页中国科学（生命科学英文版）

基　　金：supported by the National Natural Science Foundation of China(30221004)to Wang WeiWei;the National Basic Research Program from Ministry of Science and Technology of China(2011CB944100)to Yu Jun

摘　　要：Brine shrimps,Artemia(Crustacea,Anostraca),inhabit hypersaline environments and have a broad geographical distribution from sea level to high plateaus.Artemia therefore possess significant genetic diversity,which gives them their outstanding adaptability.To understand this remarkable plasticity,we sequenced the mitochondrial genomes of two Artemia tibetiana isolates from the Tibetan Plateau in China and one Artemia urmiana isolate from Lake Urmia in Iran and compared them with the genome of a low-altitude Artemia,A.franciscana.We compared the ratio of the rate of nonsynonymous(Ka) and synonymous(Ks) substitutions(Ka/Ks ratio) in the mitochondrial protein-coding gene sequences and found that atp8 had the highest Ka/Ks ratios in comparisons of A.franciscana with either A.tibetiana or A.urmiana and that atp6 had the highest Ka/Ks ratio between A.tibetiana and A.urmiana.Atp6 may have experienced strong selective pressure for high-altitude adaptation because although A.tibetiana and A.urmiana are closely related they live at different altitudes.We identified two extended termination-associated sequences and three conserved sequence blocks in the D-loop region of the mitochondrial genomes.We propose that sequence variations in the D-loop region and in the subunits of the respiratory chain complexes independently or collectively contribute to the adaptation of Artemia to different altitudes.Brine shrimps, Artemia （Crustacea, Anostraca）, inhabit hypersaline environments and have a broad geographical distribution from sea level to high plateaus. Artemia therefore possess significant genetic diversity, which gives them their outstanding adaptability. To understand this remarkable plasticity, we sequenced the mitochondrial genomes of two Artemia tibetiana iso- lates from the Tibetan Plateau in China and one Artemia urmiana isolate from Lake Urmia in Iran and compared them with the genome of a low-altitude Artemia, A. franciscana. We compared the ratio of the rate of nonsynonymous （Ka） and synonymous （Ks） substitutions （Ka/Ks ratio） in the mitochondrial protein-coding gene sequences and found that atp8 had the highest Ka/Ks ratios in comparisons of A. franciscana with either A. tibetiana or A. urmiana and that atp6 had the highest Ka/Ks ratio be- tween A. tibetiana and A. urmiana. Atp6 may have experienced strong selective pressure for high-altitude adaptation because although A. tibetiana and A. urmiana are closely related they live at different altitudes. We identified two extended termina- tion-associated sequences and three conserved sequence blocks in the D-loop region of the mitochondrial genomes. We propose that sequence variations in the D-loop region and in the subunits of the respiratory chain complexes independently or collectively contribute to the adaptation of Artemia to different altitudes.

关 键 词：mitochondrial genome Artemia tibetiana sequence variation high plateau species 

分 类 号：Q78[生物学—分子生物学]