Living species’ genes encode their complexity, but where do these genes come from? The University of Helsinki researchers answered long-standing questions about the formation of tiny regulatory genes and outlined a method that generates their DNA palindromes.
Under the right conditions, these palindromes can evolve into microRNA genes. The human genome contains ca. 20,000 genes that are used for the construction of proteins. Actions of these classical genes are coordinated by thousands of regulatory genes, the smallest of which encode microRNA molecules that are 22 base pairs in length.
While the number of genes remains relatively constant, occasionally new genes emerge during evolution. Similar to the genesis of biological life, the origin of new genes has continued to fascinate scientists.
All RNA molecules require palindromic runs of bases that lock the molecule into its functional conformation. Importantly, the chances of random base mutations gradually forming such palindromic runs are extremely small, even for the simple microRNA genes.
Hence, the origin of these palindromic sequences has puzzled researchers. Experts at the Institute of Biotechnology, University of Helsinki, Finland resolved this mystery, describing a mechanism that can instantaneously generate complete DNA palindromes and thus create new microRNA genes from previously noncoding DNA sequences.