A history of exposure to infection has marked our genomes |
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Traces of ancient viruses which infected our ancestors millions of years ago are more widespread in us than previously thought.
A study
shows how extensively viruses from as far back as the dinosaur era still thrive
in our genetic material.
It sheds
light on the origins of a big proportion of our genetic material, much of which
is still not understood.
The
scientists investigated the genomes of 38 mammals including humans, mice, rats,
elephants and dolphins.
The
research was carried out at Oxford University, the Aaron Diamond AIDS Research
Centre in New York and the Rega Institute in Belgium.
It is
reported in the journal Proceedings of the National Academy of Sciences.
One of the
viruses was found to have invaded the genome of a common ancestor around 100
million years ago with its remnants discovered in almost every mammal in the
study.
Another
infected an early primate with the result that it was found in apes, humans and
other primates as well.
The work
established that many of these viruses lost the ability to transfer from one
cell to another.
Instead
they evolved to stay within their host cell where they have profilerated very
effectively - spending their entire life cycle within the cell.
Forced
choice
The
researchers found evidence of the viruses multiplying so extensively within
mammals' genomes that they have been compared to an outbreak of disease.
The senior
author of the study, Dr Robert Belshaw from Oxford University's Zoology
Department, said: "This is the story of an epidemic within every animal's
genome, a story which has been going on for 100 million years and which
continues today.
"We
suspect that these viruses are forced to make a choice: either to keep their
'viral' essence and spread between animals and species. Or to commit to one
genome and then spread massively within it."
The study
shows that the viruses involved have lost a gene called envwhich is responsible
for transmission between cells.
Known as
endogenous retroviruses, these micro-organisms have gone on to become 30 times
more abundant in their host cells.
The study
is one of many attempting to understand the full complexity of the human
genome.
Astonishingly,
only 1.5% of the genetic material in our cells codes for human life. Half of
the rest is sometimes described as "junk DNA" with no known function,
and the other half consist of genes introduced by viruses and other parasites.
Positive
services
According
to the lead author, Dr Gkikas Magiorkinis, "much of the dark matter in our
genome plays by its own rules, in the same way as an epidemic of an infectious
disease but operating over millions of years.
"Learning
the rules of this ancient game will help us understand their role in health and
disease."
This raises
the extraordinary scenario of our DNA serving as an environment in which
viruses can evolve - a micro-ecology within the double-helix of our genetic
material.
There is
evidence that they can provide positive services. For example the protein
syncytin - derived from a virus - helps develop the placenta.
Dr Belshaw
says that endogenous retroviruses (ERVs) are not known to have any obvious or
direct health effects.
"But
there could be effects we're not picking up on or things we could even take
advantage of if we detect ERVs moving around or expressing proteins as a result
of cancer or infection."
The study
was supported by the Wellcome Trust and the Royal Society.
Related Article:
"Recalibration of Knowledge" – Jan 14, 2012 (Kryon channelled by Lee Carroll) - (Subjects: Channelling, God-Creator, Benevolent Design, New Energy, Shift of Human Consciousness, (Old) Souls, Reincarnation, Gaia, Old Energies (Africa,Terrorists, Cuba, Iran, North Korea, Venezuela ... ), Weather, Rejuvenation, Akash, Nicolas Tesla / Einstein, Cold Fusion, Magnetics, Lemuria, Atomic Structure (Electrons, Particles, Polarity, Self Balancing, Magnetism), Entanglement, "Life is necessary for a Universe to exist and not the other way around", DNA, Humans (Baby getting ready, First Breath, Stem Cells, Embryonic Stem Cells, Rejuvenation), Global Unity, ... etc.) - (Text Version)
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