昆虫科Membracidae的树蝇已经进化出了扩大而精致的胸廓结构,据推测,这涉及与翅膀共享的基因的增选表达。这里,我们研究了前胸和翅膀之间的相似性与生长的关系。我们的研究表明,前胸的个体发育与Membracidae的翅膀相似,但不是外群。使用转录组学,我们确定了与翻译和蛋白质合成相关的基因,它们是相互上调的。这些基因与eIF2,eIF4/p70S6K和mTOR途径有关,并且在调节细胞生长和增殖中具有已知的作用。我们发现,前胸的物种特异性差异生长模式最早始于第三龄,这表明附肢模式基因的表达早在变态蜕皮之前就发生了。我们建议,与增长和大小确定相关的网络是与机翼共享的更可能的机制。然而,需要阐明前胸和翅膀共享基因上游的调节因子,以证实是否发生了共同选择。最后,我们相信,当我们理解这一壮观的进化创新时,区分导致前突大小的机制和调节前突形状的机制将是有帮助的。
Treehoppers of the insect family
Membracidae have evolved enlarged and elaborate pronotal structures, which is hypothesized to involve co-opted expression of genes that are shared with the wings. Here, we investigate the similarity between the pronotum and wings in relation to growth. Our study reveals that the ontogenetic allometry of the pronotum is similar to that of wings in
Membracidae, but not the outgroup. Using transcriptomics, we identify genes related to translation and protein synthesis, which are mutually upregulated. These genes are implicated in the eIF2, eIF4/p70S6K and mTOR pathways, and have known roles in regulating cell growth and proliferation. We find that species-specific differential growth patterning of the pronotum begins as early as the third instar, which suggests that expression of appendage patterning genes occurs long before the metamorphic molt. We propose that a network related to growth and size determination is the more likely mechanism shared with wings. However, regulators upstream of the shared genes in pronotum and wings need to be elucidated to substantiate whether co-option has occurred. Finally, we believe it will be helpful to distinguish the mechanisms leading to pronotal size from those regulating pronotal shape as we make sense of this spectacular evolutionary innovation.