The Economist has an interesting brief report today on one possible explanation for the 97% of our genetic material that seems not to be a part of any gene – in at least one case, it seems the DNA involved was once part of a retrotransposon, i.e. a virus, which has now forgotten how to spread beyond its host. The theory is that the proteins generated by this DNA somehow confer protection against infection by other, bad retroviruses. Now – here’s my question – if this stuff produces proteins, why is it considered “junk” rather than part of our genome?

The technical article is available in the September 2 issue of “Current Biology”
(subscription required for full text).