Biology Reference
In-Depth Information
microbial and viral community that give and take to various extents from the
entity as a whole. Where along this gradient TEs will ultimately be placed has yet
to be determined, as the relative degree of positive and negative contributions to
the human organism remain to be elucidated.
B. The road ahead
The direction of TE research in the next decades, as with most scientific
endeavors, will be driven largerly by technological and methodological improve-
ments. Figuring heavily in these changes will be the availability of relatively
inexpensive whole genome sequencing. Low cost, ubiquitous genomic sequenc-
ing will allow for better evaluation of “natural”, unmodified, TE activity,
decreasing reliance on artificially tagged retrotransposition constructs. While
such constructs have been of tremendous importance for mobile element
research and will continue to be critical for evaluating certain molecular hypoth-
eses, sequencing-based experiments will be able to address questions surrounding
how closely modified TE constructs mirror the biological activity their natural
counterparts. We further expect that the sheer volume of sequencing data
anticipated over the coming few years will also bring changes to the
of
TE research. While novel TE biology no doubt awaits discovery amidst the
multitude of genomes that have yet to be sampled, saturation with TE diversity
information will likely lead to a deemphasis of TE discovery and annotation as an
end-in-itself, and the increasing relegation of identification and taxonomical
assignment to automated computational pipelines. Emerging technologies will
also allow us to peer more deeply into somatic activity of TEs within different
organisms, including the mechanisms of their genetic and epigenetic regulation.
As discussed above, new evidence suggesting that TE activity in the soma is
higher than once believed opens several avenues for exploration in the arena of
impacts on organismal fitness and on human health in particular. The ultimate
consequences of somatic TE activity on both cancer and aging is currently
unknown, and the elucidation of TE impact in these areas will require detailed
analysis across diverse tissues. Arguably, the most important findings of the past
several years have revolved around the discovery novel cellular regulatory
systems for controlling TE activity. These include the regulation of retrotran-
sposition by posttranscriptional processing of TE expression and by members of
the APOBEC protein family, the evidence of small RNA pathways playing a role
in repressing mammalian retrotransposons, and the involvement of DNA repair
in regulation of TE activity. The presence of these systems across diverse taxa
speaks to the threat posed by unchecked TE proliferation. Further understanding
of these regulatory mechanisms, and how they may interact with gene regulatory
networks, will continue to be fertile areas of investigation. In addition, the ability
to survey epigenetic markers at a genomic scale,
focus
in multiple tissues and
