Lineage-resolved analysis of embryonic gene expression evolution in C. elegans and C. briggsae

What constraints govern the evolution of gene expression patterns across
development remains a fundamental question. Single-cell RNA-sequencing can
detail these constraints by systematically profiling homologous cells. The
conserved invariant embryonic lineage of C. elegans and C. briggsae makes
them ideal for comparing cell-type gene expression across evolution.
Measuring the spatiotemporal divergence of gene expression across
embryogenesis, we find a high level of similarity in gene expression
programs between species despite tens of millions of years of evolutionary
divergence. Nonetheless, thousands of genes show divergence in their
cell-type-specific expression patterns, with enrichment for functions in
environmental response and behavior. Neuronal cell types show higher
divergence than others, such as the intestine and germline. This work
identifies likely constraints on the evolution of developmental gene
expression.