Discussion in 'Other Health News and Research' started by natasa778, Nov 18, 2013.
Also on ScienceDaily now: http://www.sciencedaily.com/releases/2013/11/131119230442.htm
Apart from the fact that ''junk'' doesn't seem to be ''junk'' at all, this sentence cought my attention:
(...) two "junk" viruses can combine to cause disease -- we've seen this many times in animals already. ERVs have been shown to cause cancer when activated by bacteria in mice with weakened immune systems.'
Thanks for that link!
another interesting bit:
This is especially interesting in the context of that paper that just came our about MS-linked HERV reactivation following EBV infection, and how this COMBINATION of events is likely linked to disease pathogenesis.
So the 'genetic' predisposition to some diseases might well turn out to be actually linked do VIRAL genes in our DNA, and how their expression is regulated by external events ...
Here are some other references specifically to (re)activated HERV-K in some serious diseases: leukemia, breast cancer, teratocarcinoma, melanoma, gonadolblastomas, rheumatoid arthritis, thrombocythemia, AIDS, etc. (I haven't run out of references, only energy.)
The known characteristics of HERV-K sequences in humans do not distinguish them from patterns of retroviral sequences in other species where a particular retrovirus is known to be active. The specific sequences are distinctive indications of a unique active infection in humans at some time since divergence from chimpanzees, but there is nothing to indicate this has ended. HERV-K113 is even capable of producing intact virions.
Recent work showing that previous genome maps had missed many copies of HERV-K113 hidden in centromeres reveals that this particular HERV has been much more active in modern humans than in Neanderthals or Denisovans, early humans for which we now have preliminary genomes. (Centromeres are highly repetitious sequences in the middle of chromosomes, telomeres are repetitious sequences at the ends. You can think of both as a kind of handle cellular machinery uses to grab chromosomes and tease them apart during mitosis. They have generally been assumed to be non-coding regions.)
We have some evidence that genes specific to Neanderthals and Denisovans did make it into modern humans, however these appear to be rare. The only plausible way modern humans could have ended up with 100 or more full-length insertions of the same HERV is to assume it has been active very recently (in evolutionary terms), since both Neanderthals and Denisovans died out 50,000 years ago. This strongly implies that there was horizontal transmission of genetic information between human subspecies. This would have been even more likely than transmission of retroviral infections between modern chimpanzees and modern humans, as happened with SIV and HIV.
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