中文题名 / Chinese title: 肉鳍鱼鳍的个体发育阐明具指手部的起源
英文题名 / English title: Sarcopterygian fin ontogeny elucidates the origin of hands with digits.
作者 / Authors: Woltering JM, Irisarri I, Ericsson R, Joss JMP, Sordino P, Meyer A, Meyer A.
期刊 / Journal: Science Advances
年份 / Year: 2020
DOI: 10.1126/sciadv.abc3510
论文链接 / Article: https://doi.org/10.1126/sciadv.abc3510
摘要来源 / Abstract source: https://europepmc.org/article/MED/32875118

英文摘要原文 / Original English abstract
How the hand and digits originated from fish fins during the Devonian fin-to-limb transition remains unsolved. Controversy in this conundrum stems from the scarcity of ontogenetic data from extant lobe-finned fishes. We report the patterning of an autopod-like domain by hoxa13 during fin development of the Australian lungfish, the most closely related extant fish relative of tetrapods. Differences from tetrapod limbs include the absence of digit-specific expansion of hoxd13 and hand2 and distal limitation of alx4 and pax9, which potentially evolved through an enhanced response to shh signaling in limbs. These developmental patterns indicate that the digit program originated in postaxial fin radials and later expanded anteriorly inside of a preexisting autopod-like domain during the evolution of limbs. Our findings provide a genetic framework for the transition of fins into limbs that supports the significance of classical models proposing a bending of the tetrapod metapterygial axis.

摘要依据的主要发现 / Findings based on the abstract
澳洲肺鱼鳍中存在表达 hoxa13 的类似远端肢区，但缺少四足动物若干与指形成相关的表达扩展。该模式提示指发育程序先出现在轴后鳍辐骨中，随后向前扩展。
Australian lungfish fins express hoxa13 in an autopod-like developmental domain but lack several digit-specific expression expansions seen in tetrapods. The pattern suggests that the digit program arose in postaxial fin radials before expanding anteriorly.

摘要依据的结论 / Conclusions based on the abstract
手部可能通过改造已有的鳍远端发育程序形成，而非出现完全全新的发育区域。
Hands evolved through modification of an existing distal-fin developmental program rather than the appearance of an entirely new domain.

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