View Full Version : Did retroviruses help make us human?

29-09-16, 17:36

29-09-16, 22:13
Fascinating. Wish I was a gene scientist doing all those researches :)
We are partially viruses.

30-09-16, 00:16
Now, this is the most eye opening scientific discovery I read for some time! Sure, I read a story that most likely our mitochondrial DNA is of viral or bacterial origin, but I couldn't imagine that we are actually full of viral genome. Probably most of "junk" DNA and not only. Ha, what a story!

One answer may come from another retrovirus that plagues domestic sheep, creating an infectious form of lung cancer. Unlike the koala retrovirus, the Jaagsiekte sheep retrovirus continues to circulate from sheep to sheep, just like a normal virus, but it has also inserted itself into the sheep’s DNA. Ravinder Kanda, a paleovirologist at the Oxford Brooks University in the U.K., says that those sheep that carry a copy of the retroviral DNA are immune to infection from the circulating retrovirus. Dual function. It cause lung cancer and also protects them from infections of similar retrovirus. It is like sheep got natural "flu" shot, though with a serious side effect.
Also another proof that some viral infections can cause cancer.

Some viruses helped us to evolve to be human.

A follow-up study in Nature Genetics (http://www.nature.com/ng/journal/v48/n1/full/ng.3449.html), published in early 2016, found another, HERV-H, which produced RNA molecules that also switch other genes on and off. The 13 HERV-H switches identified by Reijo Pera and Wysocka’s team help keep the early embryonic cells pluripotent, ready for any job as an adult cell. When the researchers blocked the production of HERV-H’s RNA molecules, they stopped embryo development in its tracks. Further experiments showed that HERVH-derived RNAs are also required to turn adult cells back into pluripotent stem cells.
“This DNA, what we used to think of as junk DNA, is actually modulating our development,” Reijo Pera says.
This pair of studies followed on the heels of a 2015 paper in Cell Stem Cell (http://www.ncbi.nlm.nih.gov/pubmed/25658370) that showed researchers could identify the specific stage of development of an embryonic cell based on which set of endogenous retroviruses were active. When the embryo had just one or two cells, it had the most endogenous retroviruses active, says Jonathan Göke, a computational biologist at the Genome Institute of Singapore and first author of the 2015 study. As the embryo got larger, viral activity dropped dramatically, though it still continued in specific groups of cells as the fetus developed.
“We know that they’re active. We know that they’re important, but we still don’t know exactly what they do,” he says

30-09-16, 00:17
Fascinating. Wish I was a gene scientist doing all those researches :)
We are partially viruses.
In my next life I'll be geneticist. ;)

30-09-16, 09:13

but if such an intrusion happened in our prehistory of which we have DNA genomes, I guess the event should be detectable