Discovery of 155 New Microgenes Support Evidence that Modern Humans are Still Evolving

Researchers find 155 new microgenes that lend credence to the idea that modern humans are still in the process of evolving.

Microgenes

Nearly 7 million years ago, modern humans diverged from their chimpanzee ancestors, but they have since continued to evolve. Within the human lineage, 155 new genes that spontaneously developed from small fragments of our DNA have been discovered. A few of these "microgenes" are predicted to be linked to human-specific diseases, and some of these new genes are thought to have their origins in the early evolution of mammals.

Scientist Nikolaos Vakirlis from the Biomedical Sciences Research Center Alexander Fleming, better known as BSRC Fleming in Vari, Greece, stated that this project began in 2017 due to his interest in the evolution of novel genes and understanding their origins. It was put on hold for a while until another study with some very intriguing data was published, at which point Vakirlis could begin this work.

In the other study, a group of scientists from the University of California, San Francisco, compiled a list of microproteins made by non-coding regions-previously referred to as "junk DNA"-and published it in the journal Science.

Possibly Biologically Meaningful

To compare humans to other vertebrate species, the researchers compiled an ancestral tree using the previously published dataset of functionally relevant new genes. They studied how these genes have changed throughout evolution and discovered 155 that emerged from distinctive DNA regions. However, these genes developed from scratch; new genes can emerge from duplication events that already exist in the genome.

Scientist Aoife McLysaght from Trinity College Dublin said it was thrilling to be working on something so novel as beginning to understand these tiny sizes of DNA. McLysaght is the senior author of the study. The microgenes really straddle the line between what can be deduced from a genome sequence and the point where it is difficult to determine whether it has biological significance.

Genes and Their Roles

44 of these 155 new genes are linked to growth defects in cell cultures, highlighting their significance for preserving a healthy living system. Since these genes are unique to humans, direct testing is challenging. The effects that these novel genes might have on the body must be investigated in other ways, say researchers. Vakirlis and his group looked at DNA patterns that might indicate whether these genes are involved in particular diseases.

Three of these 155 new genes have disease-related DNA markers that suggest associations with conditions like Alazami syndrome, retinitis pigmentosa, and muscular dystrophy. In addition to disease, the researchers discovered a new gene linked to human heart tissue. This gene, which showed how quickly a gene can evolve into becoming essential for the body, appeared in humans and chimpanzees shortly after the species split from gorillas.

Future research into the potential functions of these microgenes and whether or not they might be directly connected to any diseases, according to Vakirlis, will be very interesting.

Small Gene, Big Possibilities

Because they are so challenging to study, these genes are easy to ignore, but McLysaght believes that in the future, people will realize that these genes need to be examined and taken into account. There may be a lot more information in the human genome that is functionally significant if the research team is correct in their assumptions, PhysOrg reports.

This work of Vakirlis, McLysaght, and their colleagues was recently published in the journal Cell Reports.