Analyzing Horizontal Transfer of Transposable Elements on a Large Scale: Challenges and Prospects

Whoever compares the genomes of distantly related species might find aberrantly high sequence similarity at certain loci. Such anomaly can only be explained by genetic material being transferred through other means than reproduction, that is, a horizontal transfer (HT). Between multicellular organisms, the transferred material will likely turn out to be a transposable element (TE). Because TEs can move between loci and invade chromosomes by replicating themselves, HT of TEs (HTT) profoundly impacts genome evolution. Yet, very few studies have quantified HTT at large taxonomic scales. Indeed, this task currently faces difficulties that range from the variable quality of available genome sequences to limitations of analytical procedures, some of which have been overlooked. Here we review the many challenges that an extensive analysis of HTT must overcome, we expose biases and limits of current methods, suggest solutions or workarounds, and reflect upon approaches that could be developed to better quantify this phenomenon. With the large amount of genomic resources now available, horizontal transfer of transposable elements can be studied as an evolutionary process, rather than as isolated cases. We discuss some of the difficulties encountered in detecting and counting such transfers and propose guidelines and directions for future research in this area.
Source: BioEssays - Category: Molecular Biology Authors: Tags: Prospects & Overviews Source Type: research