It has been recently discovered that new genes can originate de novo from non-coding DNA, and several biological traits including expression or sequence composition form a continuum from non-coding sequences to conserved genes. In this paper, using yeast genes I test whether the integration of new genes into cellular networks, and their structural maturation shows such a continuum by analyzing their changes with gene age. I show that 1) the number of regulatory, protein-protein and genetic interactions increase continuously with gene age, although with very different rates. New regulatory interactions emerge rapidly within a few million years, while the number of protein-protein and genetic interactions increases slowly, with a rate of 2-2.25 x 10-8 per year and 4.8 x 10-8 per year, respectively. 2) Gene essentiality evolves relatively quickly: the youngest essential genes appear in proto genes ~14 my old. 3) In contrast to interactions, the secondary structure of proteins and their robustness to mutations indicate that new genes face a bottleneck in their evolution: proto-genes are characterized with high beta strand content, high aggregation propensity and low robustness against mutations, while conserved genes with lower strand content and higher stability, most likely due to the higher probability of gene loss among young genes and accumulation of neutral mutations.
- Received April 15, 2013.
- Accepted August 27, 2013.
- Copyright © 2013, The Genetics Society of America