Amazing Science: Retroviruses

Posted on November 28, 2007  Comments (3)

One of the great things about writing this blog is I find myself more focused on reading about interesting science. Retroviruses are very interesting and frankly amazing. Darwin’s Surprise by Michael Specter, The New Yorker:

A retrovirus stores its genetic information in a single-stranded molecule of RNA, instead of the more common double-stranded DNA. When it infects a cell, the virus deploys a special enzyme, called reverse transcriptase, that enables it to copy itself and then paste its own genes into the new cell’s DNA. It then becomes part of that cell forever; when the cell divides, the virus goes with it. Scientists have long suspected that if a retrovirus happens to infect a human sperm cell or egg, which is rare, and if that embryo survives – which is rarer still – the retrovirus could take its place in the blueprint of our species, passed from mother to child, and from one generation to the next, much like a gene for eye color or asthma.

When the sequence of the human genome was fully mapped, in 2003, researchers also discovered something they had not anticipated: our bodies are littered with the shards of such retroviruses, fragments of the chemical code from which all genetic material is made. It takes less than two per cent of our genome to create all the proteins necessary for us to live. Eight per cent, however, is composed of broken and disabled retroviruses, which, millions of years ago, managed to embed themselves in the DNA of our ancestors. They are called endogenous retroviruses, because once they infect the DNA of a species they become part of that species. One by one, though, after molecular battles that raged for thousands of generations, they have been defeated by evolution. Like dinosaur bones, these viral fragments are fossils. Instead of having been buried in sand, they reside within each of us, carrying a record that goes back millions of years. Because they no longer seem to serve a purpose or cause harm, these remnants have often been referred to as “junk DNA.” Many still manage to generate proteins, but scientists have never found one that functions properly in humans or that could make us sick.

How amazing is that? I mean really think about it: it is incredible. The whole article is great. Related: Old Viruses Resurrected Through DNADNA for once species found in another species’ GenesNew Understanding of Human DNARetrovirus overview (Tulane)Cancer-Killing Virus

3 Responses to “Amazing Science: Retroviruses”

  1. Curious Cat Science Blog » 8 Percent of the Human Genome is Old Virus Genes
    September 2nd, 2008 @ 8:39 am

    “about 8 percent of the human genome is made up of viruses that once attacked our ancestors…”

  2. Curious Cat Science and Engineering Blog » Resurrection of the Human IRGM Gene
    March 8th, 2009 @ 3:49 pm

    […] lineages. We suggest that the rebirth or restoration of the gene coincided with the insertion of an endogenous retrovirus, which now serves as the functional promoter driving human gene expression. We suggest that either […]

  3. Ten Things Everyone Should Know About Science » Curious Cat Science and Engineering Blog
    March 20th, 2011 @ 9:08 pm

    […] consider is something about bacteria and/or viruses. You can maybe include them under genes, but viruses and bacteria are amazing in the very strange things they do with genes and I think that is worthy […]

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