23andMe on the biparental inheritance of mitochondrial DNA and more

23andMelogoIn my former blog post inF.A.Q. for 23andMe: what if I have mitochondrial DNA from Pa? I meditated on 23andMe‘s capability of detecting paternal mitochondrial DNA in their customers’ saliva with their Illumina microarray chips scanning around 2000 mitochondrial single nucleotide variants. Published here the initial answer of the 23andMe Editorial Team to this fairly technical, but nevertheless crucial question with permission granted. Besides, I am happy to report that I am working on a blogterview with one of the key member of 23andMe’s Research Team. Hopefully I’ll be able to get back to you with some first-hand information on the science and technology behind the personal genome service of 23andMe and on how 23andMe can facilitate academic research.

Dear Attila Csordas,

Thank you for your interest in 23andMe’s research mission. The question of paternal inheritance of mtDNA is a fascinating one, and the debate in the literature has continued over the past couple of decades. Currently, there is little evidence for paternal inheritance of mtDNA, outside of isolated individuals. However, the array platform lets us resolve multiple SNP states independently. 23andMe’s technology and throughput may indeed provide a novel way to address the question. We will include the question in our consideration of research projects. In the meantime, here are a couple of articles discussing the subject:

Bandelt et al., “More evidence for non-maternal inheritance of mitochondrial DNA?”
Chinnery, “The Transmission and Segregation of Mitochondrial DNA in Homo Sapiens” in Human Mitochondrial DNA and the Evolution of Homo Sapiens.


The Editorial Team at 23andMe

The question is crucial for a personalized genetics company like 23andMe providing Maternal Ancestry Tree service for the customers based on the exclusively maternal inheritance of mitochondrial DNA. As one of my correspondent partner wrote:

“even a single such event (transmission of mtDNA from the father to the offspring) along one’s lineage would mess up the assumption that mitochondria were tracing the maternal lineage”.

The referred Bandelt is an interesting figure: originally a mathematician specialized in human mtDNA PCR and sequencing artefacts and flaws. The conclusion of the “More evidence for non-maternal inheritance of mitochondrial DNA? papers simply:

Multiple types (or recombinant types) of quite dissimilar mitochondrial DNA from different parts of the known mtDNA phylogeny are often reported in single individuals. From re-analyses and corrigenda of forensic mtDNA data, it is apparent that the phenomenon of mixed or mosaic mtDNA can be ascribed solely to contamination and sample mix up.

This, of course could hardly be the last word on the topic so I am looking forward to further discussion here at Pimm.

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