Viral Conception How the origin of mammals could be written in our genome … by viruses. Every human being starts the same way, with a sperm and egg becoming one, 23 chromosomes from each parent contributing the genetic instructions that will one day make, well … you. But the genes, the actual DNA that writes for proteins, make up only about one one-hundredth of all the DNA in those 46 chromosomes. A full 8% of the DNA in your genome, though, are the remains of ancient viruses. A certain type of virus called a “retrovirus” is capable of inserting its genome into its host, literally writing itself into your DNA. This is the family that HIV belongs to. If a retrovirus infects an egg and inserts its genome, it can get passed down to the next generation. We are full of these remnants, as inactive but still recognizable fossils of past infections. Dr. Samuel Pfaff and his team were trying to come up with a list of genes that were turned on in a developing mouse embryo, just after sperm and egg had come together. In its earliest stages, an embryo’s cells can become any tissue (one of the ideas behind stem cell therapies). What genes make this possible? It turns out that for over 100 genes, the switches (called “promoters”) that turned them on came from a very unlikely place: viruses. WHAT?! We know that these genes must be activated in order for an embryo to correctly develop, but the switches that control them come from ancient viral infections! The genes themselves? Purely mouse.  What an odd paradox of evolution!! We need these genes on at a very precise moment, and off a short while after that. If any of it goes wrong, no baby mouse. So evolution selects these viral sequences to be the control mechanism. Could an ancient infection have been the key to the very existence of mammals? Carl Zimmer has more at The Loom.
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Viral Conception

How the origin of mammals could be written in our genome … by viruses.

Every human being starts the same way, with a sperm and egg becoming one, 23 chromosomes from each parent contributing the genetic instructions that will one day make, well … you. But the genes, the actual DNA that writes for proteins, make up only about one one-hundredth of all the DNA in those 46 chromosomes.

A full 8% of the DNA in your genome, though, are the remains of ancient viruses. A certain type of virus called a “retrovirus” is capable of inserting its genome into its host, literally writing itself into your DNA. This is the family that HIV belongs to. If a retrovirus infects an egg and inserts its genome, it can get passed down to the next generation. We are full of these remnants, as inactive but still recognizable fossils of past infections.

Dr. Samuel Pfaff and his team were trying to come up with a list of genes that were turned on in a developing mouse embryo, just after sperm and egg had come together. In its earliest stages, an embryo’s cells can become any tissue (one of the ideas behind stem cell therapies). What genes make this possible?

It turns out that for over 100 genes, the switches (called “promoters”) that turned them on came from a very unlikely place: viruses. WHAT?! We know that these genes must be activated in order for an embryo to correctly develop, but the switches that control them come from ancient viral infections! The genes themselves? Purely mouse. 

What an odd paradox of evolution!! We need these genes on at a very precise moment, and off a short while after that. If any of it goes wrong, no baby mouse. So evolution selects these viral sequences to be the control mechanism. Could an ancient infection have been the key to the very existence of mammals?

Carl Zimmer has more at The Loom.

Source: blogs.discovermagazine.com

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  1. it-s-a-drugs-bust reblogged this from ssamanthabarks
  2. kukei reblogged this from jtotheizzoe and added:
    Viral Conception How the origin of mammals could be written in our genome … by viruses. Every human being starts the...
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  7. stotheb reblogged this from jtotheizzoe and added:
    Viral Conception How the origin of mammals could be written in our genome … by viruses. Every human being starts the...
  8. tumbln-n-studyin reblogged this from jtotheizzoe
  9. ravishd reblogged this from jtotheizzoe and added:
    That is so cool.
  10. klyz reblogged this from jtotheizzoe
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  16. ifeelminuscule reblogged this from jtotheizzoe and added:
    Wow, that’s fucking weird.
  17. derekauslino reblogged this from jtotheizzoe
  18. tsumabiken reblogged this from jtotheizzoe and added:
    Fascinating stuff
  19. genome-enthusiast reblogged this from jtotheizzoe and added:
    Transposition of virus and human evolution
  20. vishnusmrti reblogged this from jtotheizzoe and added:
    Viral Conception How the origin of mammals could be written in our genome … by viruses. Every human being starts the...
  21. mrdickey reblogged this from jtotheizzoe

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