RT Journal Article
SR Electronic
T1 Re-evaluating inheritance in genome evolution: widespread transfer of LINEs between species
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 106914
DO 10.1101/106914
A1 Atma Ivancevic
A1 Daniel Kortschak
A1 Terry Bertozzi
A1 David Adelson
YR 2017
UL http://biorxiv.org/content/early/2017/02/08/106914.abstract
AB Horizontal transfer1,2 (HT) is the transmission of genetic material by means other than parent-to-offspring: a phenomenon primarily associated with prokaryotes. However, eukaryotic genomes contain transposable elements3 (TE), colloquially known as ‘jumping genes’ for their ability to replicate to new genomic locations. Long interspersed element (LINE) retrotransposons are TEs which move using a “copy and paste” mechanism, resulting in gene disruptions, chromosome rearrangements and numerous diseases such as cancer4-7. LINEs are autonomous; they can move into a new genome and immediately commence replicating. This makes them good candidates for HT. Growing evidence8-11 shows that HT is more widespread than previously believed, although questions still remain about the frequency of HT events and their long-term impact. Here we show that LINE-1 (L1) and Bovine-B (BovB)12,13, the two most abundant retrotransposon families in mammals, were initially introduced as foreign DNA via ancient HT events. Using a 503-genome dataset, we identify multiple ancient L1 HT events in plants and show that L1s infiltrated the mammalian lineage after the monotreme-therian split, in contrast with the current literature14. We also extend the BovB paradigm by identifying: more than twice the number of estimated transfer events compared to previous studies8,11; new potential blood-sucking parasite vectors and occurrences in new lineages (e.g. bats, frog). Given that these retrotransposons make up nearly half of the genome sequence in today’s mammals3, our results provide the first evidence that HT can have drastic and long-term effects on the new host genomes. This revolutionizes our perception of genome evolution to consider external factors, such as the natural introduction of foreign DNA. With the advancement of genome sequencing technologies and bioinformatics tools, we anticipate our study to be the first of many large-scale phylogenomic analyses exploring the role of HT in genome evolution.