Something old, something new, something borrowed, something red: the origin of ecologically relevant novelties in Hemiptera

• Published in: Current opinion in genetics & development 2021-08, Vol.69, p.154-162
• Main Authors: Jockusch, Elizabeth L, Fisher, Cera R
• Format: Article
• Language: English
• Subjects: Animals; Evolution, Molecular; Gene Duplication - genetics; Gene Expression Regulation - genetics; Gene Transfer, Horizontal - genetics; Genetic Variation; Hemiptera - genetics; Hemiptera - growth & development; Insecta - genetics; Phenotype; Transcriptome - genetics
• ISSN: 0959-437X; 1879-0380
• DOI: 10.1016/j.gde.2021.04.003

•Hemiptera is an ecologically successful group with extensive phenotypic novelty.•Both new genes and horizontally transferred genes make important contributions to this novelty.•Comparative transcriptomics is a powerful, flexible approach for studying phenotypic evolution.•The stage is set for fruitful multi-level comparisons into the origin of novelty.•We ask whether new genes differ from old genes in their contributions to novelty. Comparative transcriptomics, applied in an evolutionary context, has transformed the possibilities for studying phenotypic evolution in non-model taxa. We review recent discoveries about the development of novel, ecologically relevant phenotypes in hemipteran insects. These discoveries highlight the diverse genomic substrates of novelty: ‘something old’, when novelty results from changes in the regulation of existing genes or gene duplication; ‘something new’, wherein lineage-restricted genes contribute to the evolution of new phenotypes; and ‘something borrowed’, showcasing contributions of horizontal gene transfer to the evolution of novelty, including carotenoid synthesis (resulting in ‘something red’). These findings show the power and flexibility of comparative transcriptomic approaches for expanding beyond the ‘toolkit’ model for the evolution of development. We conclude by raising questions about the relationship between new genes and new traits and outlining a research framework for answering them in Hemiptera.