Zombie Genes?
On August 19, Gina Kolata reported in The New York Times that geneticists “have seen a dead gene come back to life and cause a disease.”
According to Kolata, the human genome “is riddled with dead genes, fossils of a sort, dating back hundreds of thousands of years–the genome’s equivalent of an attic full of broken and useless junk,” though some of those genes “can rise from the dead like zombies.”
Now a supposed “zombie gene” is implicated in a type of muscular dystrophy abbreviated FSHD–a hereditary disease that affects about 1 in every 20,000 people.
Kolata cites a recent Science article that begins by reviewing work dating back to the 1990s that establishes a link between FSHD and a specific region on human chromosome 4. The region contains multiple repeats of “D4Z4” DNA; people with 11 or more repeats are normal, while people who have from 1 to 10 repeats are susceptible to FSHD.
Biologists used to think that D4Z4 DNA was neither transcribed into RNA nor translated into protein. In other words, D4Z4 was thought to be biologically inactive–what some people have called “:junk DNA.” Recently, however, researchers discovered that D4Z4 DNA is transcribed, and that part of it is translated into a protein, DUX4.
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