'Selfish' DNA in animal mitochondria offers possible tool to study aging | Science Codex
Researchers at Oregon State University have discovered, for the first time in any animal species, a type of "selfish" mitochondrial DNA that is actually hurting the organism and lessening its chance to survive – and bears a strong similarity to some damage done to human cells as they age.
Such selfish mitochondrial DNA has been found before in plants, but not animals. In this case, the discovery was made almost by accident during some genetic research being done on a nematode, Caenorhabditis briggsae – a type of small roundworm.
The mitochondria generally act for the benefit of the cell, even though it is somewhat separate. But the "selfish" DNA found in some plant mitochondria – and now in animals – has major differences. It tends to copy itself faster than other DNA, has no function useful to the cell, and in some cases actually harms the cell. In plants, for instance, it can affect flowering and sometimes cause sterility.
"Worms with it had less offspring than those without, they had less muscle activity. It might suggest that natural selection doesn't work very well in this species."
What's also interesting, they say, is that the defects this selfish DNA cause in this roundworm are surprisingly similar to the decayed mitochondrial DNA that accumulates as one aspect of human aging. More of the selfish DNA is also found in the worms as they age.
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