Findings indicate that new genes can originate from repurposing segments of ancestral genes while also incorporating completely new coding regions (the segments of DNA that code for proteins). This groundbreaking idea connects the formation of entirely new genes from noncoding regions to the traditional perspective where new functions emerge from duplicated genes.
What is the origin of new genes? This is the question that a group of biological sciences researchers from the U of A aimed to explore in their latest study.
To answer this, they investigated the evolution of antifreeze proteins in fish—an important adaptation that enables fish to thrive in icy waters by stopping ice from forming through the interaction of their antifreeze proteins with ice crystals.
The researchers looked into these proteins across three unrelated fish species and found unexpected results. Although the proteins in each species are functionally and structurally alike, they evolved separately from distinct genetic origins. This occurrence, termed convergent evolution, is a unique instance of protein sequence convergence. It illustrates how similar adaptive traits—and even nearly indistinguishable protein sequences—can emerge from completely different evolutionary paths.
The research presents clear instances of various evolutionary processes that can lead to the creation of new genes. The findings reveal that new genes can develop through the reuse of fragments from ancestral genes along with the introduction of entirely new coding regions. This concept uniquely combines the idea of new gene development from noncoding regions and the more classical approach where new functions arise from gene duplication.
The study, titled “Diverse origins of near-identical antifreeze proteins in unrelated fish lineages provide insights into evolutionary mechanisms of new gene birth and protein sequence convergence,” was published in Molecular Biology and Evolution. The research involved co-authors Nathan Rives, Vinita Lamba, C-H Christina Cheng, and Xuan Zhuang. Rives and Lamba, who are Ph.D. candidates in the Zhuang Lab at U of A led by assistant professor Xuan Zhuang, are the co-first authors of the study. Cheng is a professor at the University of Illinois Urbana Champaign’s School of Integrative Biology.
The research team also introduced a new model that deepens our understanding of how new genes evolve: Duplication-Degeneration-Divergence. This model explains the emergence of new gene functions from degenerated pseudogenes—genes that once had a function but lost it. Additionally, it emphasizes how genes that seem nonfunctional or “junk” can evolve into something entirely novel, a concept that has important implications for understanding adaptation in extremely challenging environmental conditions.
In the field of molecular evolution, this research marks a significant advancement in deciphering how new genes arise and develop, providing new insights into functional innovation—essentially gene recycling and adaptation.
