Peking University, Sep. 1, 2015: Where did our genes come from? Scientists agree that new genes predominantly develop from a biological process called “gene duplication”. Recent studies have brought in a new idea: new genes might also come from non-coding DNA regions. Scientists named genes generated in this way “motherless” genes or de novo genes. How do genes develop from non-coding DNA regions? This remains a mystery. Now scientists from the Institute of Molecular Medicine, PKU are able to tell us more about it. Dr.Chuan-Yun Li’s research group published their findings in PLOS Genetics, characterizing a trilogy model for the origination of new functional proteins from ancestral long non-coding RNAs.
Li’s team and other research groups first found that ancestral long non-coding RNAs (“lncRNAs”) may act as an intermediate stage in this gene creation process. To further elucidate the mechanism, Li and his group identified 43 human-specific motherless genes. For 92.9% of these genes, the corresponding regions in monkey or chimpanzee encode lncRNAs, rather than proteins. To explain why these new genes originate from some lncRNA loci but not from other loci, they analyzed the loci of these motherless genes, and found that they are GC-rich genes. The GC-rich property allows the potential novel genes to maintain a stable open reading frame (as stop codons are AT-rich), increasing their chances of being selected as functional genes. Their data further suggested natural selection’s role in this process: although motherless genes are very likely to emerge by chance, some of them have acquired protein-level functions, based on the signatures of purifying selection.
Previously, Li’s group established a knowledgebase called RhesusBase (www.rhesusbase.org). It provides a foundation for functional interrogation of human evolution in the context of non-human primates.
This project is supported by the National Basic Research Program of China (973 Program) and the National Natural Science Foundation of China.
The trilogy model for the origination of new functional proteins
For the original PLOS Genetics paper, please click: http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1005391
Acknowledgement: we are really grateful to Dr. Chuan-Yun Li, since the news release is revised by himself personally, in order to make it understandable to non-professionals.
Reported by: Li Yike
Edited by: Choisum Kwok
