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http://www.biomedcentral.com/news/20040514/01
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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.”
“It does not challenge the idea of a mitochondrial DNA molecular clock or structure of genealogical trees.”
“But they are not going to overturn our view of human evolution. The implications are not that dramatic.“
“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.”
Mitochondrial DNA recombination is the process by which genetic material is exchanged between different mitochondrial DNA molecules. This can result in the creation of new combinations of genes, leading to genetic diversity.
Mitochondrial DNA recombination occurs through a process called homologous recombination, in which two DNA molecules with similar sequences exchange genetic material.
The main benefit of mitochondrial DNA recombination is the creation of genetic diversity within a population. This can lead to increased adaptability and resilience to changing environments.
No, mitochondrial DNA recombination is limited to organisms with mitochondria, such as eukaryotes. Prokaryotes, which lack mitochondria, do not undergo mitochondrial DNA recombination.
Yes, mitochondrial DNA recombination is a random process that occurs during cell division. The specific combinations of genes that are exchanged are not predetermined, but rather occur by chance.