- Author: Kathy Keatley Garvey
ScienceDaily reported on the research in its Oct. 28th edition.
The UC Davis Department of Entomology and Nematology team included Brian Johnson and Johnson lab researchers W. Cameron Jasper and Joey Atallah; and molecular geneticist Joanna Chiu. Other co-authors were Timothy Linksvayer of the University of Pennsylvania, Philadelphia, and Daniel Friedman, then a UC Davis undergraduate student in the Artyom Kopp lab.
“Whether coding or regulatory sequence change is more important to the evolution of phenotypic novelty is one of biology's major unresolved questions. The field of evo-devo has shown that in early development changes to regulatory regions are the dominant mode of genetic change, but whether this extends to the evolution of novel phenotypes in the adult organism is unclear. Here we conduct ten RNA-Seq experiments across both novel and conserved tissues in the honey bee to determine to what extent post-developmental novelty is based on changes to the coding regions of genes. We make several discoveries. First, we show that with respect to novel physiological functions in the adult animal, positively selected tissue-specific genes of high expression underlie novelty by conferring specialized cellular functions. Such genes are often, but not always taxonomically restricted genes (TRGs). We further show that positively selected genes, whether TRGs or conserved genes, are the least connected genes within gene expression networks. Overall, this work suggests that the evo-devo paradigm is limited, and that the evolution of novelty, post-development, follows additional rules. Specifically, evo-devo stresses that high network connectedness (repeated use of the same gene in many contexts) constrains coding sequence change as it would lead to negative pleiotropic effects. Here we show that in the adult animal, the converse is true: genes with low network connectedness (TRGs and tissue-specific conserved genes) underlie novel phenotypes by rapidly changing coding sequence to perform new specialized functions.”
Links:
Read research paper, “Large Scale Coding Sequence Change Underlies the Evolution of Post-Developmental Novelty in Honey Bees,” Molecular Biology and Evolution
Read "Bee's knees for identifying genetic triggers of novel adult traits," ScienceDaily news story