Swank Samantha, Sanger Thomas J, Stuart Yoel E
Department of Biology Loyola University Chicago Chicago Illinois USA.
Ecol Evol. 2021 Oct 22;11(22):15484-15497. doi: 10.1002/ece3.8226. eCollection 2021 Nov.
Appendages have been reduced or lost hundreds of times during vertebrate evolution. This phenotypic convergence may be underlain by shared or different molecular mechanisms in distantly related vertebrate clades. To investigate, we reviewed the developmental and evolutionary literature of appendage reduction and loss in more than a dozen vertebrate genera from fish to mammals. We found that appendage reduction and loss was nearly always driven by modified gene expression as opposed to changes in coding sequences. Moreover, expression of the same genes was repeatedly modified across vertebrate taxa. However, the specific mechanisms by which expression was modified were rarely shared. The multiple routes to appendage reduction and loss suggest that adaptive loss of function phenotypes might arise routinely through changes in expression of key developmental genes.
在脊椎动物进化过程中，附肢已经减少或消失了数百次。这种表型趋同可能是由远缘脊椎动物类群中共同的或不同的分子机制所导致的。为了进行研究，我们回顾了从鱼类到哺乳动物等十多个脊椎动物属的附肢减少和消失的发育与进化文献。我们发现，附肢的减少和消失几乎总是由基因表达的改变驱动的，而非编码序列的变化。此外，同一基因的表达在不同脊椎动物类群中反复发生改变。然而，基因表达改变的具体机制却很少相同。附肢减少和消失的多种途径表明，功能表型的适应性丧失可能经常通过关键发育基因表达的变化而出现。
