小柯机器人

英国伦敦大学玛丽女王学院José M. Martín-Durán等研究人员合作通过环节动物功能基因组学揭示双侧对称动物生命周期的起源。相关论文于2023年1月25日在线发表在《自然》杂志上。

研究人员展示了躯干形成的时间变化（即异时性），这是幼虫和双侧对称动物生命周期多样化的基础。研究人员用转录组和表观基因组分析方法对环节动物Owenia fthemiformis和另外两种环节动物的生命周期进行了染色体尺度的基因组测序。研究人员发现，O. fusiformis的采食幼虫躯干发育推迟到变态前阶段，而非采食幼虫躯干发育开始于原肠胚发育后，并具有Capitella teleta的逐渐变态，以及Dimorphilus gyrociliatus的直接发育胚胎。值得注意的是，这也发生在其他双侧对称动物的所谓“头幼虫”中，其中O. fusiformis幼虫表现出广泛的转录组相似性。

总之，这些发现表明，头部和躯干形成的时间解耦（正如在头部幼虫中观察到的那样）促进了双侧对称幼虫的演化。这与目前流行的观点不同，后者提出了基因调控程序的共择或创新，从而解释了幼虫和成虫的起源。

据悉，在所有主要的动物谱系中都存在中间幼虫的间接发育，这使得幼虫成为动物演化的大多数场景的中心。然而，幼虫是如何演化的仍然存在争议。

附：英文原文

Title: Annelid functional genomics reveal the origins of bilaterian life cycles

Author: Martn-Zamora, Francisco M., Liang, Yan, Guynes, Kero, Carrillo-Baltodano, Allan M., Davies, Billie E., Donnellan, Rory D., Tan, Yongkai, Moggioli, Giacomo, Seudre, Ocane, Tran, Martin, Mortimer, Kate, Luscombe, Nicholas M., Hejnol, Andreas, Marltaz, Ferdinand, Martn-Durn, Jos M.

Issue&Volume: 2023-01-25

Abstract: Indirect development with an intermediate larva exists in all major animal lineages1, which makes larvae central to most scenarios of animal evolution2,3,4,5,6,7,8,9,10,11. Yet how larvae evolved remains disputed. Here we show that temporal shifts (that is, heterochronies) in trunk formation underpin the diversification of larvae and bilaterian life cycles. We performed chromosome-scale genome sequencing in the annelid Owenia fusiformis with transcriptomic and epigenomic profiling during the life cycles of this and two other annelids. We found that trunk development is deferred to pre-metamorphic stages in the feeding larva of O.fusiformis but starts after gastrulation in the non-feeding larva with gradual metamorphosis of Capitella teleta and the direct developing embryo of Dimorphilus gyrociliatus. Accordingly, the embryos of O.fusiformis develop first into an enlarged anterior domain that forms larval tissues and the adult head12. Notably, this also occurs in the so-called ‘head larvae’ of other bilaterians13,14,15,16,17, with which the O.fusiformis larva shows extensive transcriptomic similarities. Together, our findings suggest that the temporal decoupling of head and trunk formation, as maximally observed in head larvae, facilitated larval evolution in Bilateria. This diverges from prevailing scenarios that propose either co-option9,10 or innovation11 of gene regulatory programmes to explain larva and adult origins.

DOI: 10.1038/s41586-022-05636-7

Source: https://www.nature.com/articles/s41586-022-05636-7

Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html