Humans continue to evolve after nearly seven million years

By Mark Waghorn via SWNS

Humans are continuing to evolve after nearly seven million years, according to new research.

Scientists have identified 155 'microgenes' that spontaneously arose from tiny sections of DNA - since the split from our chimpanzee ancestors.

Some date back to the ancient origin of mammals - with a few linked to diseases, scientists say.

An international team created an ancestral tree comparing Homo sapiens to other vertebrate species.

It showed the genes arose from scratch rather than from duplication events that already existed in the genome.

First author Dr. Nikolaos Vakirlis, of the Biomedical Sciences Research Center 'Alexander Fleming' Vari, Greece, said: "This project started back in 2017. I was interested in novel gene evolution and figuring out how these genes originate.

"It was put on ice for a few years, until another study got published that had some very interesting data, allowing us to get started on this work."

An analysis found 44 of the genes are associated with growth defects in cell cultures - demonstrating their importance in maintaining a healthy, living system.

They are specific to humans - making direct testing difficult. Dr. Vakirlis and colleagues linked them to illnesses by examining patterns found within the DNA.

The study in Cell Reports opened the door to explore their effects on the body in more detail.

Senior author Professor Aoife McLysaght, of Trinity College Dublin, said: "It was quite exciting to be working in something so new.

"When you start getting into these small sizes of DNA, they are really on the edge of what is interpretable from a genome sequence, and they are in that zone where it is hard to know if it is biologically meaningful."

Two had DNA markers pointing to connections with the wasting disorder muscular dystrophy and retinitis pigmentosa which leads to vision loss.

Another contained chemicals that have been linked to increased risk of dwarfism, or Alazami syndrome.

Apart from disease, the researchers also found a new gene that is associated with human heart tissue.

This gene emerged in humans and chimps right after the split from gorillas - and shows just how fast a gene can evolve to become essential for the body.

Dr. Vakirlis said: "It will be very interesting in future studies to understand what these microgenes might do and whether they might be directly involved in any kind of disease."

The findings shed light on previous global studies of our DNA which have suggested natural selection has recently made changes and continues to do so.

Certain traits created by genetic mutations help an organism survive or reproduce. Such mutations are more likely to be passed on - so they increase in frequency.

Added McLysaght: "These genes are convenient to ignore because they are so difficult to study. But I think it will be increasingly recognized they need to be looked at and considered.

"If we are right in what we think we have here, there is a lot more functionally relevant stuff hidden in the human genome."