Hox genes, transcription factors – what makes a species

Two very interesting studies recently related to understanding the distinction of species at the genetic level.

sciencedaily.com 2019.05.27 Scientists uncover a trove of genes that could hold key to how humans evolved

Researchers at the Donnelly Centre in Toronto have found that dozens of genes, previously thought to have similar roles across different organisms, are in fact unique to humans and could help explain how our species came to exist.

These genes code for a class of proteins known as transcription factors, or TFs, which control gene activity. TFs recognize specific snippets of the DNA code called motifs, and use them as landing sites to bind the DNA and turn genes on or off.

sciencedaily.com 2019.09.29 Biological ‘rosetta stone’ brings scientists closer to deciphering how the body is built

Every animal, from an ant to a human, contains in their genome pieces of DNA called Hox genes. Architects of the body, these genes are keepers of the body’s blueprints; they dictate how embryos grown into adults, including where a developing animal puts its head, legs and other body parts.

Scientists have long searched for ways to decipher how Hox genes create this body map; a key to decoding how we build our bodies.

Now an international group of researchers from Columbia University and the Spanish National Research Council (CSIC) based at the Universidad Pablo de Olavide in Seville, Spain have found one such key: a method that can systematically identify the role each Hox gene plays in a developing fruit fly.

Hox genes are ancient; they can be found across all animal species. Even primitive jellyfish have them. Each type of organism has different combinations of these genes. Fruit flies have eight Hox genes, while humans have 39.

These genes work by producing special proteins called transcription factors, which work together with similar proteins called Hox cofactors to bind to different segments of DNA and turn many other genes on and off at just the right time — a Rube Goldberg machine of microscopic proportions.