A conserved paint box underlies color pattern diversity in Estrildid finches.

Many animals exhibit typical color patterns that have been linked to key adaptive functions, yet the developmental mechanisms establishing these crucial designs remain unclear. Here, we surveyed color distribution in the plumage across a large number of passerine finches. Despite extreme apparent pattern diversity, we identified a small set of conserved color regions whose combinatory association can explain all observed patterns. We found these domains are instructed by signals from embryonic somites and lateral plate mesoderm, and through profiling and comparative analyses, produced a molecular map marking putative color domains in the developing skin. This revealed cryptic pre-patterning common to differently colored species, uncovering a simple molecular landscape underlying extensive color pattern variation. Overall design: identification of molecules spatially restricted to presumptive color domains, three dorsal and four ventral regions of the embryonic skin at hh28, in triplicate