期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2022
卷号：119
期号：9
DOI：10.1073/pnas.2119210119
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Significance
When organisms access unexploited ecological opportunities, species diversification often follows, yet the mechanisms underlying such transitions are poorly understood. Water striders transited from terrestrial to water surface life some 200 Mya, aided by the evolution of superhydrophobic bristles and increased leg length, both required for standing and moving on water. We identified genes involved in both bristle density and leg length, suggesting that these two traits are genetically correlated. Strikingly, these genes are involved in cell division, thus explaining their dual role in leg growth and bristle density. In addition, we identified molecular changes that account in part for the differences in bristle density across species. We propose that pleiotropy might facilitate diversification by impacting several adaptive traits simultaneously.
Access to hitherto unexploited ecological opportunities is associated with phenotypic evolution and often results in significant lineage diversification. Yet our understanding of the mechanisms underlying such adaptive traits remains limited. Water striders have been able to exploit the water–air interface, primarily facilitated by changes in the density of hydrophobic bristles and a significant increase in leg length. These two traits are functionally correlated and are both necessary for generating efficient locomotion on the water surface. Whether bristle density and leg length have any cellular or developmental genetic mechanisms in common is unknown. Here, we combine comparative genomics and transcriptomics with functional RNA interference assays to examine the developmental genetic and cellular mechanisms underlying the patterning of the bristles and the legs in
Gerris buenoi and
Mesovelia mulsanti, two species of water striders. We found that two duplication events in the genes
beadex and
taxi led to a functional expansion of the paralogs, which affected bristle density and leg length. We also identified genes for which no function in bristle development has been previously described in other insects. Interestingly, most of these genes play a dual role in regulating bristle development and leg length. In addition, these genes play a role in regulating cell division. This result suggests that cell division may be a common mechanism through which these genes can simultaneously regulate leg length and bristle density. We propose that pleiotropy, through which gene function affects the development of multiple traits, may play a prominent role in facilitating access to unexploited ecological opportunities and species diversification.
关键词：encorrelated traitsevolution and adaptationpleiotropycell divisionwater striders
