【目的】动物典型的单一染色体线粒体基因组在甲胁虱属Hoplopleura已裂化成多个线粒体微环染色体。本研究旨在通过测定太平洋甲胁虱Hoplopleura pacifica的线粒体基因组来推测甲胁虱属祖先线粒体核型。【方法】利用Illumina HiSeq X Te...【目的】动物典型的单一染色体线粒体基因组在甲胁虱属Hoplopleura已裂化成多个线粒体微环染色体。本研究旨在通过测定太平洋甲胁虱Hoplopleura pacifica的线粒体基因组来推测甲胁虱属祖先线粒体核型。【方法】利用Illumina HiSeq X Ten高通量测序技术对太平洋甲胁虱裂化线粒体基因组进行测定,分析其结构特征与变异情况;用最大似然法和邻接法构建7科7属15种吸虱的系统发育树;用简约法推测甲胁虱属祖先线粒体核型。【结果】太平洋甲胁虱线粒体基因组测序获得29个基因(11个蛋白质编码基因,16个tRNA基因以及2个rRNA基因),且不均匀地分布于10个线粒体微环染色体上,每个线粒体微环染色体的编码区包括1~5个基因,大小在690~1773 bp之间。甲胁虱属内物种线粒体微环染色体组成差异较小,与吸虱亚目(Anoplura)其他属相比,甲胁虱属线粒体微环染色体的基因组成和基因排列有差异,但这种差异仅限于tRNA基因。进化树强烈支持吸虱亚目分为两大进化支,一个大的进化支包括甲胁虱科(Hoplopleuridae)、多板虱科(Polyplacidae)、血虱科(Haematopinidae)和微胸虱科(Microthoraciidae),另一个大的进化支包括虱科(Pediculidae)、阴虱科(Pthiridae)和猴虱科(Pedicinidae)。甲胁虱属祖先线粒体核型由12个线粒体微环染色体组成,每个线粒体微环染色体由一个编码区和一个非编码区构成,编码区包含1~6个基因。【结论】本研究首次测定并分析了太平洋甲胁虱裂化线粒体基因组,并与迄今为止测序的另外2种甲胁虱的线粒体基因组进行了比较,推测出甲胁虱属祖先线粒体核型。展开更多
Meiotic recombination is a deeply conserved process within eukaryotes that has a profound effect on patterns of natural genetic variation. During meiosis homologous chromosomes pair and undergo DNA double strand break...Meiotic recombination is a deeply conserved process within eukaryotes that has a profound effect on patterns of natural genetic variation. During meiosis homologous chromosomes pair and undergo DNA double strand breaks generated by the Spo11 endonuclease. These breaks can be repaired as crossovers that result in reciprocal exchange between chromosomes. The frequency of recombination along chromosomes is highly variable, for example, crossovers are rarely observed in heterochromatin and the centromeric regions. Recent work in plants has shown that crossover hotspots occur in gene promoters and are associated with specific chromatin modifications, including H2 A.Z. Meiotic chromosomes are also organized in loop-base arrays connected to an underlying chromosome axis, which likely interacts with chromatin to organize patterns of recombination.Therefore, epigenetic information exerts a major influence on patterns of meiotic recombination along chromosomes, genetic variation within populations and evolution of plant genomes.展开更多
文摘Meiotic recombination is a deeply conserved process within eukaryotes that has a profound effect on patterns of natural genetic variation. During meiosis homologous chromosomes pair and undergo DNA double strand breaks generated by the Spo11 endonuclease. These breaks can be repaired as crossovers that result in reciprocal exchange between chromosomes. The frequency of recombination along chromosomes is highly variable, for example, crossovers are rarely observed in heterochromatin and the centromeric regions. Recent work in plants has shown that crossover hotspots occur in gene promoters and are associated with specific chromatin modifications, including H2 A.Z. Meiotic chromosomes are also organized in loop-base arrays connected to an underlying chromosome axis, which likely interacts with chromatin to organize patterns of recombination.Therefore, epigenetic information exerts a major influence on patterns of meiotic recombination along chromosomes, genetic variation within populations and evolution of plant genomes.
