Endogenous Retroviruses (ERVs/retrotransposons) are a class of transposons which exhibit great similarity to and, in some cases, are derived from retroviruses. ERVs have long been known to be components of eukaryotic genomes, and, in many cases, have persisted in those genomes for millennia, and in humans, these components make around up 10% of the total genome, though they are largely found in non-coding regions of the genome.
Researchers at Sweden's Lund University have determined that some ERVs serve as "docking platforms" for TRIM28, a protein which halts the transcription of ERVs as well as coding sequences to which they are adjacent. That known genomic regulators of the central dogma only compose 2% of the human genome, a fifth of the extent to which ERVS are represented, and that ERVs are transposable in the genome might indicate that this regulation might have far-reaching effects on human gene expression and, potentially, behavior and evolution as well. Another curious aspect of this research to consider is that many ERVs with potential roles in regulating the development of the human CNS are not found in our closest primate relatives, and thus may shed particular light on the differences which may exist between our brains, their development and their evolution.
Per Ludvik Brattås, Marie E. Jönsson, Liana Fasching, Jenny Nelander Wahlestedt, Mansoureh Shahsavani, Ronny Falk, Anna Falk, Patric Jern, Malin Parmar, Johan Jakobsson. TRIM28 Controls a Gene Regulatory Network Based on Endogenous Retroviruses in Human Neural Progenitor Cells. Cell Reports, 2017; 18 (1): 1 DOI: 10.1016/j.celrep.2016.12.010