Six loci of nucleolar organizer region (NOR) were detected in genomic in situ hybridization (GISH) of cotton (Gossypium). NOR was the characteristic of 45S rDNA but could be generated by genomic DNA (gDNA) extracted f...Six loci of nucleolar organizer region (NOR) were detected in genomic in situ hybridization (GISH) of cotton (Gossypium). NOR was the characteristic of 45S rDNA but could be generated by genomic DNA (gDNA) extracted from Gossypium species as probe. With twice FISH to the same mitotic cell of G. herbaceum or G. hirsutum, number, position and size for NORs generated from 45S rDNA and gDNA were identified largely similar or even the same. The NORs with gDNA as probe were therefore permanently defined as GISH-NORs. GISH-NORs from G. hirsutum and G. raimondii mitotic images were all terminal types. Four and two GISH-NORs from G. herbaceum (var. africanum) were terminal and centromere types, respectively. Six GISH-NORs in G. hirsutum were chromosome mapped with two in A- and four in D-subgenomes. There were also GISH-NORs in mitotic image of G. raimondii with its own gDNA as probe. From mitotic image of G. herbaceum with its own gDNA as probe, GISH-NOR could not be observed but non-whole- recovery of hybridized signals was distinguished. These non-whole-recovery of hybridized signals were detected on long arm terminals of most chromosomes and especially existed in nearly half long arm of a pair of chromosomes in G. herbaceum gDNA probed itself GISH image, which may be possibly induced by low copy genes within the regions rather than inter-subgenomic segment translocations. GISH-NORs in G. hirsutum mitotic images were dominantly observed when gDNAs from D and A genome species were used as probes and block, respectively, but not when the reverse probe and block gDNA from the two diploid progenitor genomes were designed. There may be two speculations to this special phenomenon: rDNA concerted evolution; content of rDNA in genome D more than genome A.展开更多
We evaluated nine plastid （matK, rbcL, rpoCl, rpoB, rp136-rpsS, ndhJ, trnL-F, tmrnH-psbA, accD） and two nuclear （ITS and ITS2） barcode loci in family Zingiberaceae by analyzing 60 accessions of 20 species belongin...We evaluated nine plastid （matK, rbcL, rpoCl, rpoB, rp136-rpsS, ndhJ, trnL-F, tmrnH-psbA, accD） and two nuclear （ITS and ITS2） barcode loci in family Zingiberaceae by analyzing 60 accessions of 20 species belonging to seven genera from India. Bidirectional sequences were recovered for every plastid locus by direct sequencing of polymerase chain reaction （PCR） amplicons in all the accessions tested. However, only 35 （58%） and 4o accessions （66~） yielded ITS and ITS2 sequences, respectively, by direct sequencing. In different bioinformatics analyses, matK and rbcL consistently resolved 15 species （75%） into monophyletic groups and five species into two para- phyletic groups. The 173 ITS sequences, including 138 cloned sequences from 23 accessions, discriminated only 12 species （6o%）, and the remaining species were entered into three paraphyletic groups. Phylogenetic and genealogic analyses of plastid and ITS sequences imply the possible occurrence ofnatural hybridizations in the evolutionary past in giving rise to species paraphyly and intragenomic ITS heterogeneity in the species tested. The results support using matK and rbcL loci for barcoding Zingiberaceae members and highlight the poor utility of iTS and the highly regarded ITS2 in barcoding this family, and also caution against proposing ITS loci for barcoding taxa based on limited sampling.展开更多
Cytokines mediate their pleiotropic actions by binding to and activating theircell-surface receptors.So far,people have learned much about their biological characteristics,biochemical profile,and the interaction or mo...Cytokines mediate their pleiotropic actions by binding to and activating theircell-surface receptors.So far,people have learned much about their biological characteristics,biochemical profile,and the interaction or modulation between cytokines and theirreceptors as well.However,people have no idea about what relationship of cytokines withtheir receptors in phylogeny exists.展开更多
核糖体DNA的ITS序列作为现代分子生物学系统发育及物种鉴定中的一种有效的分子标记被广泛使用。通过对3株野生香菇个体细胞总DNA的提取,nr DNA ITS序列的扩增、回收、克隆、测序,分析其ITS序列对构建系统发育树及r RNA二级结构的影响。...核糖体DNA的ITS序列作为现代分子生物学系统发育及物种鉴定中的一种有效的分子标记被广泛使用。通过对3株野生香菇个体细胞总DNA的提取,nr DNA ITS序列的扩增、回收、克隆、测序,分析其ITS序列对构建系统发育树及r RNA二级结构的影响。结果表明:香菇个体细胞内ITS序列存在较高的多样性,即致同进化不完全现象。由此推论ITS序列并不适用于香菇菌株的鉴定和系统发育研究,而在其他真菌中是否也有此现象有待进一步研究。展开更多
The neutral theory raised by Motoo Kimura in 1968 asserts that 'the great majority of evolutionary changes at the molecular level, as revealed by comparative studies of protein and DNA sequences. are caused not by...The neutral theory raised by Motoo Kimura in 1968 asserts that 'the great majority of evolutionary changes at the molecular level, as revealed by comparative studies of protein and DNA sequences. are caused not by Darwinian selection but by random drift of selectively neutral or nearly neutral mutants'.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.301 70501)the National Basic Research Program of China(Grant No.2004CB117300)the Hi-Tech Research and De-velopment Program of China(Grant No.2003AA207051).
文摘Six loci of nucleolar organizer region (NOR) were detected in genomic in situ hybridization (GISH) of cotton (Gossypium). NOR was the characteristic of 45S rDNA but could be generated by genomic DNA (gDNA) extracted from Gossypium species as probe. With twice FISH to the same mitotic cell of G. herbaceum or G. hirsutum, number, position and size for NORs generated from 45S rDNA and gDNA were identified largely similar or even the same. The NORs with gDNA as probe were therefore permanently defined as GISH-NORs. GISH-NORs from G. hirsutum and G. raimondii mitotic images were all terminal types. Four and two GISH-NORs from G. herbaceum (var. africanum) were terminal and centromere types, respectively. Six GISH-NORs in G. hirsutum were chromosome mapped with two in A- and four in D-subgenomes. There were also GISH-NORs in mitotic image of G. raimondii with its own gDNA as probe. From mitotic image of G. herbaceum with its own gDNA as probe, GISH-NOR could not be observed but non-whole- recovery of hybridized signals was distinguished. These non-whole-recovery of hybridized signals were detected on long arm terminals of most chromosomes and especially existed in nearly half long arm of a pair of chromosomes in G. herbaceum gDNA probed itself GISH image, which may be possibly induced by low copy genes within the regions rather than inter-subgenomic segment translocations. GISH-NORs in G. hirsutum mitotic images were dominantly observed when gDNAs from D and A genome species were used as probes and block, respectively, but not when the reverse probe and block gDNA from the two diploid progenitor genomes were designed. There may be two speculations to this special phenomenon: rDNA concerted evolution; content of rDNA in genome D more than genome A.
基金financial support (BT/ PR8349/NDB/51/136/2006 19/01/2007–19-01/2010) from the Department of Biotechnology, Government of India
文摘We evaluated nine plastid （matK, rbcL, rpoCl, rpoB, rp136-rpsS, ndhJ, trnL-F, tmrnH-psbA, accD） and two nuclear （ITS and ITS2） barcode loci in family Zingiberaceae by analyzing 60 accessions of 20 species belonging to seven genera from India. Bidirectional sequences were recovered for every plastid locus by direct sequencing of polymerase chain reaction （PCR） amplicons in all the accessions tested. However, only 35 （58%） and 4o accessions （66~） yielded ITS and ITS2 sequences, respectively, by direct sequencing. In different bioinformatics analyses, matK and rbcL consistently resolved 15 species （75%） into monophyletic groups and five species into two para- phyletic groups. The 173 ITS sequences, including 138 cloned sequences from 23 accessions, discriminated only 12 species （6o%）, and the remaining species were entered into three paraphyletic groups. Phylogenetic and genealogic analyses of plastid and ITS sequences imply the possible occurrence ofnatural hybridizations in the evolutionary past in giving rise to species paraphyly and intragenomic ITS heterogeneity in the species tested. The results support using matK and rbcL loci for barcoding Zingiberaceae members and highlight the poor utility of iTS and the highly regarded ITS2 in barcoding this family, and also caution against proposing ITS loci for barcoding taxa based on limited sampling.
基金Project supported by the National Natural Science Foundation of China.
文摘Cytokines mediate their pleiotropic actions by binding to and activating theircell-surface receptors.So far,people have learned much about their biological characteristics,biochemical profile,and the interaction or modulation between cytokines and theirreceptors as well.However,people have no idea about what relationship of cytokines withtheir receptors in phylogeny exists.
文摘核糖体DNA的ITS序列作为现代分子生物学系统发育及物种鉴定中的一种有效的分子标记被广泛使用。通过对3株野生香菇个体细胞总DNA的提取,nr DNA ITS序列的扩增、回收、克隆、测序,分析其ITS序列对构建系统发育树及r RNA二级结构的影响。结果表明:香菇个体细胞内ITS序列存在较高的多样性,即致同进化不完全现象。由此推论ITS序列并不适用于香菇菌株的鉴定和系统发育研究,而在其他真菌中是否也有此现象有待进一步研究。
基金Project supported by the National Natural Science Foundation of China.
文摘The neutral theory raised by Motoo Kimura in 1968 asserts that 'the great majority of evolutionary changes at the molecular level, as revealed by comparative studies of protein and DNA sequences. are caused not by Darwinian selection but by random drift of selectively neutral or nearly neutral mutants'.
文摘本研究对杜氏赖草(Leymus duthiei)及杜氏赖草长芒变种(Leymus duthiei var.longearistatus)的nrDNA ITS进行多克隆测序,探讨ITS序列在其个体内的多样性和个体间的遗传分化。序列多态性、基因谱系和rRNA基因二级结构分析表明:①由于致同进化作用,ITS序列在L. duthiei和L.duthiei var. longearistatus中可能朝Ns基因组一方发生偏向;③致同进化的驱动力可能促使不同的ITS拷贝序列在L.duthiei var. longearistatus中比在L. duthiei中更趋于一致;③ITS序列在L.duthiei和L. duthiei var. longearistatus中的遗传分化可能与它们的地理隔离有关。
