Genetic Toolkit for Feathers Existed Long Before Dinosaurs

Climate, Carbon & Geobiology

Julia Clarke, a researcher at the Jackson School of Geosciences, and collaborators have found that genes that regulate feather development are much older than the dinosaurs, a group that includes modern birds as well as ancient reptiles.

Their findings were published in the journal Molecular Biology and Evolution in November 2014.

According to their work, 86 percent of genes regulating feather formation, and 100 percent of non-keratin protein genes required to build feathers were present in the ancestors of archosaurs, the taxonomic group from which dinosaurs evolved.

The researchers discovered the pres­ence of the genes by comparing the whole-genome sequence of a chicken — technically a living dinosaur — with whole-genome sequences from 19 other animals representing various evolu­tionary lineages. Genes controlling feather development and production in chickens were found in lineages much more ancient than archosaurs, with regulatory genes spiking in ancestors to amniota, the taxonomic group where hard-shelled eggs and internal embryo development first evolved. The spike in protein-encoding genes for feathers didn’t occur until much later, with the evolution of dinosaurs, and later modern birds, from archosaur ancestors.

These findings indicate that regula­tory genes required for feathers could be a “flexible toolkit” that controlled the development of many structures, such as hair, as well as feathers. The presence of the regulatory genes in taxonomic groups older than archosaur could also mean that feather precursors may have existed more than 100 million years before more modern-looking feathers appeared in dinosaurs

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