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Researchers at Trinity College Dublin have found two new human-specific ‘microgenes’ that arose from scratch.
New research suggests modern humans continued to evolve since we split from our chimpanzee ancestors nearly 7m years ago.
Researchers examined a previously published dataset of functionally relevant new genes and created an ancestral tree to compare humans to other vertebrate species. From tracking the relationship of these genes across evolution, the researchers discovered 155 DNA sequences that appeared to be ‘de novo’, or evolved from scratch rather than arising from duplication. Among these new genes are two human-specific ‘microgenes’.
Of these 155 genes, three have disease-associated DNA markers that point to connections with muscular dystrophy, retinitis pigmentosa and Alazami syndrome.
The researchers also found a new gene associated with human heart tissue that is believed to have emerged in humans and chimps after they split from gorillas. This shows how quickly a gene essential to the body can evolve.
The research was conducted by Nikolaos Vakirlis from the Alexander Fleming Biomedical Sciences Research Center in Greece and Prof Aoife McLysaght of Trinity College Dublin.
“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,” said Vakirlis.
Vakirlis said the research into these new genes began in 2017 because he 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,” Vakirlis said.
Direct testing of human-specific genes is difficult and so the research team examined patterns found within the DNA that would hint at the roles the genes play.
Despite the difficulties of this study, geneticist McLysaght said it was “quite exciting” to be working on something this new.
“When you start getting into these small sizes of DNA, they’re really on the edge of what is interpretable from a genome sequence, and they’re in that zone where it’s hard to know if it is biologically meaningful,” she said.
“These genes are convenient to ignore because they’re so difficult to study, but I think it’ll be increasingly recognised that they need to be looked at and considered. If we’re right in what we think we have here, there’s a lot more functionally relevant stuff hidden in the human genome.”
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