The genetic diversity of Artemisia halodendron(Asteraceae), a constructive and dominant species in Horqin Sandy Land,was investigated to examine the genetic relationships with different hydrothermal regions in Horqin ...The genetic diversity of Artemisia halodendron(Asteraceae), a constructive and dominant species in Horqin Sandy Land,was investigated to examine the genetic relationships with different hydrothermal regions in Horqin Sandy Land. We sequenced chloroplast DNA(cp DNA) fragments(trn L–F) of 243 plants from 10 populations across the Horqin Sandy Land.The analyses of cp DNA variation identified seven haplotypes. A low level of haplotype diversity(H_d=0.706) and nucleotide diversity(π=0.0013) was detected. Haplotypes clustered into two tentative clades. Low genetic differentiation among regions was consistently indicated by hierarchical analyses of molecular variance(AMOVA). Across the sampled populations, the haplotype distributions were differentiated with hydrothermal gradients.展开更多
Species of the Pinus genus provide a classical model for studying hybrid speciation.Although studies on two narrowly distributed species(P inus funebris and P.takahasii)concluded that they originated from two widespre...Species of the Pinus genus provide a classical model for studying hybrid speciation.Although studies on two narrowly distributed species(P inus funebris and P.takahasii)concluded that they originated from two widespread species(P.sylvestris and P.densiflora)via hybrid speciation,the conclusion was based on a low number of informative restriction sites.In this study,we analyzed the sequences of four Pinus chloroplast(cp)genomes(P.sylvestris,P.densiflora,P.funebris and P.takahasii)to clarify whether hybrid speciation was involved.The complete cp-genomes of Pinus species ranged in size from 119,865 to 119,890 bp,similar to other Pinus species.Phylogenetic results based on the whole cp-genomes showed P.sylvestris clustered with P.funebris and P.takahasii,which suggested that P.sylvestris was the paternal parent in hybridization events.In an analysis of simple sequence repeats(SSRs),we detected a total of 69 SSRs repeats among the four Pinus cp-genomes;most were A or T bases.In addition,we identified divergent hotspot regions among the four Pinus cp-genomes(trnE-clpP,cemA-ycf4,petD-rpoA,psbD-trnT,and trnN-chlL),in P.sylvestris(psbD-trnT,trnN-chlL,psbB and rps8)and in P.densiflora(trnE-clpP,petD-rpoA,ycf3 intron,psbD-trnT,and trnN-chlL).The genome information found in this study provides new insights into hybrid speciation in P inus and contributes to a better understanding of the phylogenetic relationships within the Pinus genus.展开更多
Comparative analysis reveals remarkable homology between the sequences of both psbA gene nucleotidesand the inferred amino acids of sorghum, a C4 plant, and those of rice, a C3 plant. The 5'-noncoding region of so...Comparative analysis reveals remarkable homology between the sequences of both psbA gene nucleotidesand the inferred amino acids of sorghum, a C4 plant, and those of rice, a C3 plant. The 5'-noncoding region of sorghum psbA gene contains the conservative promoter elements, ' - 35' element and ' - 10' element, like the prokaryote and the promoter element, TATA box, like the eukaryote. As compared with that of the rice, an extra sequence of 7 bp is found in the leader sequence of the mRNA in the former. Using an in vitro system, it has been demonstrated that protein factor exists in sorghum chloroplast protein extract which specifically binds to the 5'-noncoding region of psbA gene. Measurement of the expression of luciferase shows a 2-5 time greater reaction of the expression plasmids pALqs which contain leader region of sorghum psbA gene than that of the expression plasmids pALqr which contain leader region of rice psbA gene in E. coli.展开更多
The chloroplast genes matK and rbcL, ribo- somal gene 18S and ITS regions of nuclear ribosomal DNA from Ephedra rhytidosperma, a species endemic to China, were sequenced and its phylogenetic position was investi- gate...The chloroplast genes matK and rbcL, ribo- somal gene 18S and ITS regions of nuclear ribosomal DNA from Ephedra rhytidosperma, a species endemic to China, were sequenced and its phylogenetic position was investi- gated. Independent and combined phylogenetic analyses for the DNA sequences from 16 taxa representing 15 species of the genus Ephedra were performed using the maximum par- simony (MP), neighbor-joining (NJ), minimum evolution (ME) and maximum likelihood (ML) methods. The results indicate that E. rhytidosperma is closely related to E. equiset- ina. The divergence time between them is estimated to be 10.85±2.44 Ma based on the results of the relative-rate tests and the evolutionary rate of rbcL gene.展开更多
基金supported by research projects 2016YFC0500907,2017FY100205,41201561,Y551821001,and 145RJYA269
文摘The genetic diversity of Artemisia halodendron(Asteraceae), a constructive and dominant species in Horqin Sandy Land,was investigated to examine the genetic relationships with different hydrothermal regions in Horqin Sandy Land. We sequenced chloroplast DNA(cp DNA) fragments(trn L–F) of 243 plants from 10 populations across the Horqin Sandy Land.The analyses of cp DNA variation identified seven haplotypes. A low level of haplotype diversity(H_d=0.706) and nucleotide diversity(π=0.0013) was detected. Haplotypes clustered into two tentative clades. Low genetic differentiation among regions was consistently indicated by hierarchical analyses of molecular variance(AMOVA). Across the sampled populations, the haplotype distributions were differentiated with hydrothermal gradients.
基金funded by Kunyu Mountain National Nature Reserve Administration。
文摘Species of the Pinus genus provide a classical model for studying hybrid speciation.Although studies on two narrowly distributed species(P inus funebris and P.takahasii)concluded that they originated from two widespread species(P.sylvestris and P.densiflora)via hybrid speciation,the conclusion was based on a low number of informative restriction sites.In this study,we analyzed the sequences of four Pinus chloroplast(cp)genomes(P.sylvestris,P.densiflora,P.funebris and P.takahasii)to clarify whether hybrid speciation was involved.The complete cp-genomes of Pinus species ranged in size from 119,865 to 119,890 bp,similar to other Pinus species.Phylogenetic results based on the whole cp-genomes showed P.sylvestris clustered with P.funebris and P.takahasii,which suggested that P.sylvestris was the paternal parent in hybridization events.In an analysis of simple sequence repeats(SSRs),we detected a total of 69 SSRs repeats among the four Pinus cp-genomes;most were A or T bases.In addition,we identified divergent hotspot regions among the four Pinus cp-genomes(trnE-clpP,cemA-ycf4,petD-rpoA,psbD-trnT,and trnN-chlL),in P.sylvestris(psbD-trnT,trnN-chlL,psbB and rps8)and in P.densiflora(trnE-clpP,petD-rpoA,ycf3 intron,psbD-trnT,and trnN-chlL).The genome information found in this study provides new insights into hybrid speciation in P inus and contributes to a better understanding of the phylogenetic relationships within the Pinus genus.
基金Project supported by the Chinese National "863" and "973" Projects.
文摘Comparative analysis reveals remarkable homology between the sequences of both psbA gene nucleotidesand the inferred amino acids of sorghum, a C4 plant, and those of rice, a C3 plant. The 5'-noncoding region of sorghum psbA gene contains the conservative promoter elements, ' - 35' element and ' - 10' element, like the prokaryote and the promoter element, TATA box, like the eukaryote. As compared with that of the rice, an extra sequence of 7 bp is found in the leader sequence of the mRNA in the former. Using an in vitro system, it has been demonstrated that protein factor exists in sorghum chloroplast protein extract which specifically binds to the 5'-noncoding region of psbA gene. Measurement of the expression of luciferase shows a 2-5 time greater reaction of the expression plasmids pALqs which contain leader region of sorghum psbA gene than that of the expression plasmids pALqr which contain leader region of rice psbA gene in E. coli.
基金supported by the Chinese National Key Project for Basic Research(“973"”)(2003CB715904)the National Natural Science Foundation of China(Grant Nos.30230030&30370105).
文摘The chloroplast genes matK and rbcL, ribo- somal gene 18S and ITS regions of nuclear ribosomal DNA from Ephedra rhytidosperma, a species endemic to China, were sequenced and its phylogenetic position was investi- gated. Independent and combined phylogenetic analyses for the DNA sequences from 16 taxa representing 15 species of the genus Ephedra were performed using the maximum par- simony (MP), neighbor-joining (NJ), minimum evolution (ME) and maximum likelihood (ML) methods. The results indicate that E. rhytidosperma is closely related to E. equiset- ina. The divergence time between them is estimated to be 10.85±2.44 Ma based on the results of the relative-rate tests and the evolutionary rate of rbcL gene.
