Massive changes in genome architecture accompany the transition to self-fertility in the filamentous fungus Neurospora tetrasperma.
Massive changes in genome architecture accompany the transition to self-fertility in the filamentous fungus Neurospora tetrasperma.
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DOI：
10.1534/genetics.111.130690
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发表时间：
2011-09
期刊：
影响因子：
3.3
通讯作者：
Taylor JW
中科院分区：
文献类型：
--
作者：
Ellison CE;Stajich JE;Jacobson DJ;Natvig DO;Lapidus A;Foster B;Aerts A;Riley R;Lindquist EA;Grigoriev IV;Taylor JW
一大片受抑制的重组围绕在自交可育真菌--四精脉孢霉的性别决定基因周围。这一区域包含了近五分之一的四精核细菌基因组，抑制重组对于自交繁殖是必要的。四精核菌的交配染色体与植物和动物的性染色体的相似性及其最近的起源(<；5MYA)，再加上长期的遗传学和细胞学研究，使这种真菌成为研究抑制重组的进化后果的理想模型。在这里，我们比较了两个交配型相反的四精核菌菌株的基因组序列，以确定结构重排是否与非重组区相关，并检查抑制重组对其内基因进化的影响。我们发现了一系列的三个反转，覆盖了大部分受抑制的重组区域，并为两种不同类型的重排机制提供了证据：最近提出的通过交错单链断裂的反转机制以及转座元件之间的异位重组机制。此外，我们还发现，交配型区域的四种核霉似乎比另一种交配型(Mat A)积累有害替代的速度更快，因此可能处于退化的早期阶段。
A large region of suppressed recombination surrounds the sex-determining locus of the self-fertile fungus Neurospora tetrasperma. This region encompasses nearly one-fifth of the N. tetrasperma genome and suppression of recombination is necessary for self-fertility. The similarity of the N. tetrasperma mating chromosome to plant and animal sex chromosomes and its recent origin (<5 MYA), combined with a long history of genetic and cytological research, make this fungus an ideal model for studying the evolutionary consequences of suppressed recombination. Here we compare genome sequences from two N. tetrasperma strains of opposite mating type to determine whether structural rearrangements are associated with the nonrecombining region and to examine the effect of suppressed recombination for the evolution of the genes within it. We find a series of three inversions encompassing the majority of the region of suppressed recombination and provide evidence for two different types of rearrangement mechanisms: the recently proposed mechanism of inversion via staggered single-strand breaks as well as ectopic recombination between transposable elements. In addition, we show that the N. tetrasperma mat a mating-type region appears to be accumulating deleterious substitutions at a faster rate than the other mating type (mat A) and thus may be in the early stages of degeneration.