Publication
Canalized gene expression during development mediates caste differentiation in ants
Publisher:
Springer Science and Business Media LLC
Date:
03-10-2022
DOI:
10.1038/S41559-022-01884-Y
Abstract: Ant colonies are higher-level organisms consisting of specialized reproductive and non-reproductive in iduals that differentiate early in development, similar to germ–soma segregation in bilateral Metazoa. Analogous to erging cell lines, developmental differentiation of in idual ants has often been considered in epigenetic terms but the sets of genes that determine caste phenotypes throughout larval and pupal development remain unknown. Here, we reconstruct the in idual developmental trajectories of two ant species, Monomorium pharaonis and Acromyrmex echinatior , after obtaining ,400 whole-genome transcriptomes. Using a new backward prediction algorithm, we show that caste phenotypes can be accurately predicted by genome-wide transcriptome profiling. We find that caste differentiation is increasingly canalized from early development onwards, particularly in germline in iduals (gynes/queens) and that the juvenile hormone signalling pathway plays a key role in this process by regulating body mass ergence between castes. We quantified gene-specific canalization levels and found that canalized genes with gyne/queen-biased expression were enriched for ovary and wing functions while canalized genes with worker-biased expression were enriched in brain and behavioural functions. Suppression in gyne larvae of Freja , a highly canalized gyne-biased ovary gene, disturbed pupal development by inducing non-adaptive intermediate phenotypes between gynes and workers. Our results are consistent with natural selection actively maintaining canalized caste phenotypes while securing robustness in the life cycle ontogeny of ant colonies.