new genes discovered in DNA that appeared “spontaneously”

Humans and chimpanzees separated about 7 million years ago. We parted ways, but continue to evolve to this day.

New genes can arise through duplication, where part of a chromosome’s genetic material doubles and lengthens the chromosome. Genetic duplication produces changes in the genome and is an important driver of evolution. However, new genes can also appear “spontaneously” from small pieces of our DNA.

Gene duplication
Biomedical scientists from Greece and Ireland have 155 new genes identified in the bundle of human genes, which were added to our DNA seemingly out of nowhere. Some of these “new” genes have their origins in ancient times, when mammals had not yet roamed the earth. Some other of these “microgenes” seem to be linked to diseases specific to humans.

“This project started in 2017 because I was interested in the evolution of new genes and wanted to know how these genes appear,” says lead author Nikolaos Vakirlis. “We were forced to put the project on hold for a few years, but when another study came out with some very interesting new data, we were able to continue our research.”

Created spontaneously
The research team used a previously published dataset of relevant new genes to create an ancestral map comparing human DNA with other vertebrate species. They superimposed the genomes and discovered that 155 “new” genes arose spontaneously from specific small DNA fragments. The researchers wanted to know more about this interesting discovery. What is this genetic information?

“It was fascinating to tackle and explore such a new subject,” says Irish researcher Aoife McLysaght from Trinity College Dublin. “If you dig deeper and deeper into these little pieces of DNA, you notice that the work is moving more and more towards the limits of what can still be analyzed. It is difficult to estimate the biological significance of the genes and genomic sequences studied. It’s a huge challenge.

Find models
Of these 155 new genes, 44 are linked to a variety of cell growth problems. These genes appear to be an important link in maintaining healthy cellular life. Since these are human genes, direct testing is difficult to perform. Scientists must therefore find another way to discover the effects that these new genes could have on the human body. Vakirlis and his team focused on patterns in DNA that could indicate whether these types of genes play a role in specific diseases.

Three of these 155 newly discovered genes have DNA markers linked to inherited diseases such as muscular dystrophy, retinitis pigmentosa (severe eye malformation) and Alazami syndrome (growth disorder). In addition to the genes linked to the disorders, the researchers also discovered a new gene linked to the development of human heart tissue. This gene appeared immediately after humans and chimpanzees split from the gorilla and shows how quickly a gene can evolve to become essential for building an organism.

Hidden treasures
“There is still a lot of work to do. I think it would be very interesting to dig deeper into these microgenes in future studies and better understand what they are capable of and whether they can be directly involved in disease,” says Vakirlis.

“It’s tempting to ignore these genes because they’re so hard to study. However, it is becoming increasingly clear that science cannot turn a blind eye to these fascinating bits of genetic material,” McLysaght said. “If our assumptions are correct and we can build on the findings of this study, there are many more relevant things like this hidden deep within the human genome waiting to be discovered.”