I run across many papers that support the hypothesis of front-loading, but never seem to find the time these days to write up blog entries that explain the findings and how they relate to FLE. So instead of just sitting on them, I thought I would share them by posting the abstracts. In the future, I hope to comment on them. If you have read the book or follow this blog, you should be able to pick out the relevance of the findings. So here’s the first one about transcription factors, which are proteins that regulate the expression of genes:
Unexpected repertoire of metazoan transcription factors in the unicellular holozoan Capsaspora owczarzaki.
Mol Biol Evol. 2010 Nov 17
Sebé-Pedrós A, de Mendoza A, Lang BF, Degnan BM, Ruiz-Trillo I.
How animals (metazoans) originated from their single-celled ancestors remains a major question in biology. As transcriptional regulation is crucial to animal development, deciphering the early evolution of associated transcription factors (TFs) is critical to understanding metazoan origins. In this study we uncovered the repertoire of seventeen metazoan TFs in the amoeboid holozoan Capsaspora owczarzaki, a representative of a unicellular lineage that is closely related to choanoflagellates and metazoans. Phylogenetic and comparative genomic analyses with the broadest possible taxonomic sampling allowed us to formulate new hypotheses regarding the origin and evolution of developmental metazoan TFs. We show that the complexity of the TF repertoire in Capsaspora owczarzaki is strikingly high, pushing back further the origin of some TFs formerly thought to be metazoan-specific, such as T-box or Runx. Nonetheless, TF families whose beginnings antedate the origin of the animal kingdom, such as homedomain or bHLH, underwent significant expansion and diversification along metazoan and eumetazoan stems.