The genetics of ray pattern variation in Caenorhabditis briggsae -: art. no. 3
The genetics of ray pattern variation in Caenorhabditis briggsae -: art. no. 3
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DOI：
10.1186/1471-2148-5-3
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发表时间：
2005-01-05
影响因子：
3.4
通讯作者：
Bohrer, JC
中科院分区：
文献类型：
--
作者：
Baird, SE;Davidson, CR;Bohrer, JC
背景：种内变异如何与形态的宏观进化变化相关？在具有衍生特征但这些特征不固定的物种中可以探讨这个问题。在线虫类的小杆线虫中，雄性尾部九对双侧外周感觉器官（射线）的排列通常是物种间差异最大的特征。射线模式的发育涉及同源基因表达模式、转化生长因子β信号传导、Wnt信号传导以及其他遗传途径的输入。在秀丽隐杆线虫中，射线模式的菌株特异性变异为研究射线模式的进化提供了切入点。一些菌株具有固定的衍生模式，其他菌株则更具可塑性，并且以相同频率呈现衍生模式和祖先模式。
结果：由变异的秀丽隐杆线虫AF16和HK104菌株杂交构建的重组近交系（RILs）表现出广泛的表型，包括一些比任一亲本菌株更极端的表型。超亲分离与秀丽隐杆线虫腹部B同源基因Cb - egl - 5的等位基因变异显著相关。至少有两个影响射线模式不同要素（射线位置和射线融合）的基因与第二个基因mip - 1连锁。与此一致的是，在RILs中射线位置和射线融合表型的分离仅部分相关。
结论：射线模式的进化涉及多个基因座的等位基因变异。其中一些基因座影响射线特性的确定，同时影响多个射线模式要素。其他基因座影响单个特征，并且不受与其他射线模式要素的协方差约束。在可能参与射线模式进化的遗传途径中，包括同源基因对前后位置信息的确定。
Background: How does intraspecific variation relate to macroevolutionary change in morphology? This question can be addressed in species in which derived characters are present but not fixed. In rhabditid nematodes, the arrangement of the nine bilateral pairs of peripheral sense organs ( rays) in tails of males is often the most highly divergent character between species. The development of ray pattern involves inputs from hometic gene expression patterns, TGFbeta signalling, Wnt signalling, and other genetic pathways. In Caenorhabditis briggsae, strain-specific variation in ray pattern has provided an entree into the evolution of ray pattern. Some strains were fixed for a derived pattern. Other strains were more plastic and exhibited derived and ancestral patterns at equal frequencies.Results: Recombinant inbred lines ( RILs) constructed from crosses between the variant C. briggsae AF16 and HK104 strains exhibited a wide range of phenotypes including some that were more extreme than either parental strain. Transgressive segregation was significantly associated with allelic variation in the C. briggsae homolog of abdominal B, Cb-egl-5. At least two genes that affected different elements of ray pattern, ray position and ray fusion, were linked to a second gene, mip-1. Consistent with this, the segregation of ray position and ray fusion phenotypes were only partially correlated in the RILs.Conclusions: The evolution of ray pattern has involved allelic variation at multiple loci. Some of these loci impact the specification of ray identities and simultaneously affect multiple ray pattern elements. Others impact individual characters and are not constrained by covariance with other ray pattern elements. Among the genetic pathways that may be involved in ray pattern evolution is specification of anteroposterior positional information by homeotic genes.