Centro Andaluz de Biología del Desarrollo (CABD), CSIC-JA-UPO Ctra. de Utrera, km1, 41013, Seville, Spain.
Málaga Biomedical Research Institute and Andalusian Centre for Nanomedicine and Biotechnology Platform, Severo Ochoa, 35, 29590, Málaga, Spain.
Nat Commun. 2023 Sep 15;14(1):5730. doi: 10.1038/s41467-023-41414-3.
The re-use of genes in new organs forms the base of many evolutionary novelties. A well-characterised case is the recruitment of the posterior spiracle gene network to the Drosophila male genitalia. Here we find that this network has also been co-opted to the testis mesoderm where is required for sperm liberation, providing an example of sequentially repeated developmental co-options. Associated to this co-option event, an evolutionary expression novelty appeared, the activation of the posterior segment determinant Engrailed to the anterior A8 segment controlled by common testis and spiracle regulatory elements. Enhancer deletion shows that A8 anterior Engrailed activation is not required for spiracle development but only necessary in the testis. Our study presents an example of pre-adaptive developmental novelty: the activation of the Engrailed transcription factor in the anterior compartment of the A8 segment where, despite having no specific function, opens the possibility of this developmental factor acquiring one. We propose that recently co-opted networks become interlocked, so that any change to the network because of its function in one organ, will be mirrored by other organs even if it provides no selective advantage to them.
基因在新器官中的重复利用构成了许多进化创新的基础。一个特征鲜明的例子是，后部气孔基因网络被招募到果蝇雄性生殖器中。在这里，我们发现该网络也被篡夺到睾丸中胚层，在那里它需要精子释放，为顺序重复的发育共选择提供了一个例子。与这种共选择事件相关的是，出现了一种进化表达的新颖性，即后部节段决定因子 engrailed 被激活到由共同的睾丸和气孔调节元件控制的前 A8 节段。增强子缺失表明，A8 节段前 engrailed 的激活不是气孔发育所必需的，但在睾丸中是必需的。我们的研究提出了一个预先适应的发育新颖性的例子： engrailed 转录因子在 A8 节段的前区被激活，尽管它没有特定的功能，但为这个发育因子获得一个功能提供了可能性。我们提出，最近被篡夺的网络变得相互锁定，因此，由于其在一个器官中的功能而对网络进行的任何改变，即使对其他器官没有选择优势，也会在其他器官中得到反映。
