Reverse transcription of genes by retroelements and its impact on evolution

The possibility of Lamarckian modes of evolution rests on the notion that phenotypic changes can either be inherited to the next generation or be converted into the genome. While the first option can be subserved by diverse epigenetic means, the latter requires back flow of information, e.g. from RNA to the genomic DNA. This reverse flow can be realized by the molecular process of reverse transcription. Retrotransposons propagate in genomes via reverse transcription and here we examine the extent to which they can induce this process in other genes. Reverse transcription can create new copies of reverse transcribed genes and propagate transcription and RT errors back into the genome. Therefore, it can significantly impact their evolution. Specifically, highly expressed genes are more likely to undergo RT, making it a potential agent of Lamarckian inheritance. Ty elements in yeast are retrotransposons that form virus like particles (VLPs) within the cytosol in which cellular mRNA can be contained, and potentially be reverse-transcribed and subsequently incorporate into the genome. High throughput sequencing assays were performed on Ty1 VLPs in order to determine their mRNA and cDNA contents. Here, we analyze these results and form a list of VLP enriched and depleted genes and of reverse transcribed genes. We see that VLP depleted genes tend to be evolutionary conserved and that VLP enrichment and depletion are highly associated with specific RNA localization.