Meeting Abstract
A long-standing question has been whether changes in gene regulation or protein sequence has made a larger contribution to phenotypic diversity seen between species. It is commonly believed that changes in cis-regulatory systems more often underlie the evolution of morphological diversity. These cis-regulatory elements typically regulate gene transcription by functioning as binding sites for transcription factors. Transcription factors (TFs) are proteins that bind to DNA in a sequence-specific manner and enhance or repress gene expression. Although, transcription factor binding domains are very well conserved, the other associated domains, largely responsible for protein-protein interactions, readily diverge among homologs. Therefore, the structure and function of transcription factors are inherently modular. This attribute is thought to allow gene-regulatory networks to evolve via transcription factor changes, and could account for the seemingly large phenotypic difference between closely related groups. Although transcription factor diversity has been correlated with increased complexity across the eukaryotic lineage, no study has been able to measure such transcription factor diversity within a specious, but highly related, clade. One of the most diverse vertebrate lineages is that of birds, and is also the tetrapod class with the most living species. Not only do birds live worldwide and range in size, but also they vary widely in morphology, physiology and behavior. Recently, 48 avian genomes representing all the major families have recently been published. In this study, we identify the major metazoan TF families and domain architectures in these genomes, as well as reptiles. We also highlight differences in TF DBD composition between birds and reptiles as well as their putative functional similarities.
