Transposable elements as genomic diseases

Abstract

Transposable elements as genomic diseases AbstractHuman disease agents can get transmitted both horizontally--through infection--and vertically--from parent to offspring. Depending on details of their evolutionary dynamics, they may increase or decrease in virulence over time. The evolutionary dynamics of bacterial transposable elements resembles that of human pathogens in these and other respects. I here briefly highlight similarities and differences in the two evolutionary processes. I also suggest that an epidemiological perspective, combined with future estimates of parameters of transposable element evolution from hundreds of genomes, may yield insights into the forces that maintain transposable elements in bacterial populations. Transposable elements as genomic diseases Abstract:Human disease agents can get transmitted both horizontally -through infection -and vertically -from parent to offspring. Depending on details of their evolutionary dynamics, they may increase or decrease in virulence over time. The evolutionary dynamics of bacterial transposable elements resembles that of human pathogens in these and other respects. I here briefly highlight similarities and differences in the two evolutionary processes. I also suggest that an epidemiological perspective, combined with future

Large-Scale Genomic Analysis Suggests a Neutral Punctuated Dynamics of Transposable Elements in Bacterial Genomes

“…In the latter case, explosive IS proliferation would be the expected outcome because weak purifying selection is unable to compensate for IS duplications (see the SI for analytical calculations). Therefore, finding weak selection rates in a proliferation biased scenario necessarily implies that host genomes are out of equilibrium and in their way to becoming fully invaded by IS [12], [25].…”

“…IS first enter host genomes through lateral gene transfer (LGT) and they can increase their copy number via transposition. The broad diversity of effects that IS exert on their hosts has turned the fate of this relationship —long-term coexistence or eventual extinction of the host due to IS proliferation—, into a matter of debate [12]. Moreover, relatively recent cases of rapid IS expansions in bacterial genomes, which have been attributed to episodes of host restriction and environmental change, raise additional questions on the causes and nature of such IS expansions [11], [13], [14].…”

What traits are carried on mobile genetic elements, and why?

“…As a result of their distinct transmission mechanisms, the interests of MGEs may not always coincide with the interests of the host genome, as they can use different means to ensure they get as many copies of themselves into the next generation (Orgel and Crick, 1980;Wagner, 2009). Whether they confer beneficial or detrimental effects on a host will depend on the selective forces exerting an effect on both the mobile element and the host chromosome.…”

Insertion sequence evolutionary patterns highlight convergent genetic inactivations and recent genomic island acquisitions among epidemic Burkholderia cenocepacia

“…They encode all the genetic information required for their mobility, including a transposase coding sequence (CDS) as well as direct repeats (DR) and inverted repeats (IR) DNA that play a role in the transposition process (Mahillon & Chandler, 1998; see http://www-is.biotoul.fr/ for a general view on IS classification issues). ISs have been described as the 'kiss of death' for a bacterial genome because of their ability to disrupt or alter gene DNA sequences and affect bacterial fitness (Wagner, 2009). This conclusion was based, in part, on the observation of a very low genetic diversity among ISs of the same family subgroup and in the same bacterial genome (Wagner, 2006).…”