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首页> 外文期刊>Journal of genetics >Ascus dysgenesis in hybrid crosses of Neurospora and Sordaria (Sordariaceae)
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Ascus dysgenesis in hybrid crosses of Neurospora and Sordaria (Sordariaceae)

机译：Ascus在神经孢子孢子和Sordaria（Sordariaceae）的杂交杂交中

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摘要

When two lineages derived from a common ancestor become reproductively isolated (e.g. Neurospora crassa and N. tetrasperma), genes that have undergone mutation and adaptive evolution in one lineage can potentially become dysfunctional when transferred into the other, since other genes have undergone mutation and evolution in the second lineage, and the derived alleles were never 'tested' together before hybrid formation. Bateson (1909), Dobzhansky (1936), and Muller (1942) recognized that incompatibility between the derived alleles could potentially make the hybrid lethal, sterile, or display some other detriment. Alternatively, the detrimental effects seen in crosses with the hybrids may result from the silencing of ascus-development genes by meiotic silencing by unpaired DNA (MSUD). Aberrant transcripts from genes improperly paired in meiosis are processed into single-stranded MSUD-associated small interfering RNA (masiRNA), which is used to degrade complementary mRNA. Recently, backcrosses of N. crassa /N. tetrasperma hybrid translocation strains with wild-type N. tetrasperma were found to elicit novel ascus dysgenesis phenotypes. One was a transmission ratio distortion that apparently disfavoured the homokaryotic ascospores formed following alternate segregation. Another was the production of heterokaryotic ascospores in eight-spored asci. Lewis (1969) also had reported sighting rare eight-spored asci with heterokaryotic ascospores in interspecific crosses in Sordaria, a related genus. Ordinarily, in both Neurospora and Sordaria, the ascospores are partitioned at the eight-nucleus stage, and ascospores in eight-spored asci are initially uninucleate. Evidently, in hybrid crosses of the family Sordariaceae, ascospore partitioning can be delayed until after one or more mitoses following the postmeiotic mitosis.
机译：当来自常见祖先的两个谱系成为生殖分离的（例如神经孢子Crassa和N.Tetrasperma）时，在转移到另一个血管片中经过突变和自适应演化的基因可能会变得功能障碍，因为其他基因经历了突变和进化在第二个谱系中，衍生的等位基因在杂交形成之前从未在一起“测试”。 Bateson（1909），Dobzhansky（1936）和Muller（1942）认识到，衍生的等位基因之间的不相容性可能使杂交致死，无菌或显示一些其他损害。或者，与杂种的十字架中，通过未配对的DNA（MSUD）的减肥可能是由抗抗菌发育基因的沉默产生的不利影响。从分裂中相当不正确的基因的异常转录物被加工成单链MSUD相关的小干扰RNA（MasiRNA），其用于降解互补的mRNA。最近，rescrosses n。crassa / n。发现具有野生型N.Tetrasperma的四孢菌杂交易位菌株引发新的Ascus Dysenesis表型。一种是显然脱离在交替隔离后形成的同核囊孢子的传动比变形。另一个是在八个刺激的ASCI中生产异质核糖孢子。刘易斯（1969年）还报道了罕见的八个刺激的八胞嘧啶，其在索拉西亚的三分之一的杂交中，患有相关的属。通常，在神经孢子菌和Sordaria中，囊孢子在八个核阶段分区，八个刺激ASCI中的囊孢子最初是不核心的。显然，在令人讨厌的杂交杂交中，在后期分配后的一种或多种微分后，可以延迟Ascospore分区。

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