Somatic polyploidization and cellular proliferation drive body size evolution in nematodes
Somatic polyploidization and cellular proliferation drive body size evolution in nematodes
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DOI：
10.1073/pnas.97.10.5285
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发表时间：
2000-05-09
影响因子：
11.1
通讯作者：
Leroi, AM
中科院分区：
文献类型：
--
作者：
Flemming, AJ;Shen, ZZ;Leroi, AM
秀丽隐杆线虫等杆状线虫的大部分皮下组织是单一的合胞体。这种合胞体的大小(以身体大小衡量)在横纹夜蛾线虫中反复进化。在身体大小的进化中，有两种细胞机制很重要：与合胞体融合的细胞数量的变化，以及合胞体脱细胞生长的程度。因此，线虫不同于哺乳动物和其他无脊椎动物，在这些无脊椎动物中，身体大小的进化仅由细胞数量的变化引起。线虫无细胞合胞生长的进化也与皮下细胞核倍性的变化有关。这些核是多倍体的，作为反复内复制的结果，这个内环反复进化。脱细胞生长和内复制之间的联系也可以在线虫突变中看到，这些突变中断了转化生长因子-β信号，导致了皮下倍体的矮化和缺陷。转化生长因子-β途径是参与线虫个体大小进化的候选途径。
Most of the hypodermis of a rhabditid nematode such as Caenorhabditis elegans is a single syncytium. The size of this syncytium (as measured by body size) has evolved repeatedly in the rhabditid nematodes. Two cellular mechanisms are important in the evolution of body size: changes in the numbers of cells that fuse with the syncytium, and the extent of its acellular growth. Thus nematodes differ from mammals and other invertebrates in which body size evolution is caused by changes in cell number alone. The evolution of acellular syncytial growth in nematodes is also associated with changes in the ploidy of hypodermal nuclei. These nuclei are polyploid as a consequence of iterative rounds of endoreduplication, and this endocycle has evolved repeatedly. The association between acellular growth and endoreduplication is also seen in C. elegans mutations that interrupt transforming growth factor-beta signaling and that result in dwarfism and deficiencies in hypodermal ploidy. The transforming growth factor-beta pathway is a candidate for being involved in nematode body size evolution.