Mitochondrial DNA recombines

[iansmith]

Finding in muscle of patient with myopathy may change thinking on inheritance, say authors | By Cathy Holding



Recombination occurs in human mitochondrial DNA, says a team from the Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, in a “proof of concept” paper in Science this week that they say overturns current dogma of maternal inheritance and non-recombination.

Investigating the basis for a mitchondrial myopathy in a patient described in 2002, members of Kraytsberg's group had discovered that his muscle contained about 90% paternal mtDNA carrying a detrimental mutation responsible for the disease, Khrapko told The Scientist by email.

Using a restriction enzyme recognizing only paternal sequence, and single-molecule polymerase chain reaction (PCR) to amplify it, 33 out of 450 PCR clones from the subject's muscle tissue were found to contain both maternal and paternal sequence. Several recombinants contained more than one breakpoint—segments that join polymorphisms of different (paternal/maternal) descent—and three breakpoint hotspots were described as “highly significant.”

http://www.biomedcentral.com/news/20040514/01

[selfAdjoint]

Oops!. Now what becomes of the mitochondrial clock? And mEve?

[iansmith]

If you read further down you will find these quotes

The team leader
“It does not challenge the idea of a mitochondrial DNA molecular clock or structure of genealogical trees.”

Adam Eyre-Walker
“But they are not going to overturn our view of human evolution. The implications are not that dramatic.“

and

“One aspect of this may be that a little bit of paternal leakage actually is generating a slightly higher mutation rate, so it's possible that a proportion of the mutations we see in mitochondrial DNA are actually generated from these paternal leakage events—which would be intriguing.”

“the work could have implications for dating our most recent female common ancestor sometimes referred to as Eve.“

“You can date [her] by using mitochondrial DNA because it appears to be inherited solely through the maternal line,” he said. “It will change that picture.”

This study has open a big can of worm