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A fundamental focus of evolutionary-developmental biology is uncovering the genetic mechanisms responsible for the gain and loss of characters. One approach to this question is to investigate changes in the coordinated expression of a group of genes important for the development of a character of interest (a gene regulatory network). Here we consider the possibility that modifications to the wing gene regulatory network (wGRN), as defined by work primarily done in Drosophila melanogaster, were involved in the evolution of wing dimorphisms of the pea aphid (Acyrthosiphon pisum). We hypothesize that this may have occurred via changes in expression levels or duplication followed by sub-functionalization of wGRN components. To test this, we annotated members of the wGRN in the pea aphid genome and assessed their expression levels in first and third nymphal instars of winged and wingless morphs of males and asexual females. We find that only two of the 32 assessed genes exhibit morph-biased expression. We also find that three wing genes (apterous (ap), warts (wts), and decapentaplegic (dpp)) have undergone gene duplication. In each case, the resulting paralogs show signs of functional divergence, exhibiting either sex-, morph-, or stage-specific expression. Two gene duplicates, wts2 and dpp3, are of particular interest with respect to wing dimorphism, as they exhibit a wingless male-specific isoform and wingless male-biased expression, respectively. These results supplement our understanding of trends in developmental gene network evolution, such as side-stepping pleiotropic constraint via duplication and sub-functionalization, underlying the emergence of novel phenotypes.
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This content will become publicly available on February 25, 2026
Gene duplication captures morph-specific promoter usage in the evolution of aphid wing dimorphisms
Understanding how morphology evolves requires identifying the types of mutations that contribute to changes in development. We integrated comparative genomics and transcriptomics to reconstruct the evolution and regulation offollistatinparalogs in relation to the evolution of aphid winged and wingless morphs. We find that different pea aphidfollistatinduplicates play an essential molecular role in both the male and female wing dimorphisms, linking the genetic and environmental control of morph determination in each sex, respectively. We also find that an ancestralfollistatingene likely had multiple promoters and that thefollistatinduplicates that evolved wingless-specific expression retained only the ancestral wingless-specific promoter. Our work provides a roadmap for how alternative promoter usage and subsequent gene duplication can enable the evolution of animal form.
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- Award ID(s):
- 2305817
- PAR ID:
- 10587070
- Publisher / Repository:
- Proceedings of the National Academy of Sciences of the United States of America
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 122
- Issue:
- 8
- ISSN:
- 0027-8424
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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