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【bio-news】向日葵的物种形成标示了转座因子在进
Sunflower speciation highlights roles for transposable elements in evolution
In a finding that furthers our understanding of how hybridization may contribute to genome changes and the evolution of new species, researchers have found that the genomes of three sunflower species that arose in evolution as hybrids of the same two parental types have undergone a massive proliferation of genetic entities known as transposable elements. The findings are reported by Mark Ungerer and colleagues at Kansas State University and appear in the October 24th issue of the journal Current Biology, published by Cell Press.
Theory predicts that for diploid species--that is, those possessing two sets of chromosomes, like most animals and plants--the origin of new species through inter-species hybridization may be facilitated by rapid reorganization of genomes. Previous work on three independently derived hybrid sunflower species has validated this mode of speciation by documenting novel structural rearrangements in their chromosomes, as well as large-scale increases in nuclear DNA content. The nuclear-genome size differences between the hybrids and their parental taxa occur in spite of the fact that all species possess the same number of chromosomes and are diploids.
In the new work, the researchers have determined that the genome size differences between the hybrid and parental sunflower species are associated with a massive proliferation of transposable genetic elements that has occurred independently in the genome of each hybrid species. Transposable elements, made famous by Barbara McClintock in her study of their behavior in maize, are related to infectious retroviruses and are capable of multiplying and inserting themselves at different points throughout a host genome. They are found in virtually all eukaryotic genomes.
The new findings not only add an interesting twist to the origin of new sunflower species through hybridization, but also suggest that the sunflower system may emerge as an excellent model group for studying the natural forces influencing the activation and proliferation of transposable elements in plants. This is because in addition to their hybrid origins, each of the three hybrid species is adapted to, and evolved in, a so-called abiotically extreme environment--two of the species are found in desert environments, while the third is adapted to salt marshes. Both hybridization and abiotic stress have been implicated as natural agents of activation and proliferation of transposable elements. 本人认领该文件,48小时后若未回复,请其他战友自由认领. Sunflower speciation highlights roles for transposable elements in evolution向日葵的物种形成
向日葵的
向日葵的物种形成标示了转座因子在物种进化中的作用
In a finding that furthers our understanding of how hybridization may contribute to genome changes and the evolution of new species, researchers have found that the genomes of three sunflower species that arose in evolution as hybrids of the same two parental types have undergone a massive proliferation of genetic entities known as transposable elements. The findings are reported by Mark Ungerer and colleagues at Kansas State University and appear in the October 24th issue of the journal Current Biology, published by Cell Press.
一项新研究发现能帮助我们理解杂交是怎样促进基因组发生改变和新物种的的进化。研究者发现经两个相同的亲本杂交进化形成的三个向日葵物种其基因组转座子增加。该研究结果由勘萨斯州大学Mark Ungerer和同事发现并发表在细胞出版社出版的《当前生物学》10月份的第24期上。
Theory predicts that for diploid species--that is, those possessing two sets of chromosomes, like most animals and plants--the origin of new species through inter-species hybridization may be facilitated by rapid reorganization of genomes. Previous work on three independently derived hybrid sunflower species has validated this mode of speciation by documenting novel structural rearrangements in their chromosomes, as well as large-scale increases in nuclear DNA content. The nuclear-genome size differences between the hybrids and their parental taxa occur in spite of the fact that all species possess the same number of chromosomes and are diploids.
该原理预测二倍体生物（即含有两套染色体的物种如大多数动物和植物）通过种间杂交产生的新物种可能是经过基因组的快速重组促进形成的。前期关于三种不同来源的杂交向日葵的研究验证了文献上报道的物种形成模式---新的染色体的重排和核内DNA含量的大量增加。虽然这些物种都是二倍体并且含有相同数量的染色体但是杂交体和亲本间核基因组大小仍不相同。
In the new work, the researchers have determined that the genome size differences between the hybrid and parental sunflower species are associated with a massive proliferation of transposable genetic elements that has occurred independently in the genome of each hybrid species. Transposable elements, made famous by Barbara McClintock in her study of their behavior in maize, are related to infectious retroviruses and are capable of multiplying and inserting themselves at different points throughout a host genome. They are found in virtually all eukaryotic genomes.
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作者:admin@医学,生命科学 2011-03-14 17:11
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