This week the NY Times had
an interesting opinion column on mitochondrial replacement, a procedure
currently under review by the FDA. The idea is that there is a cohort of
inheritable diseases based on defects in the mitochondrial genome. In the
embryo the mitochondria are all derived from the fertilized egg so the defects
are passed from the female partner. Thus the approach for potential parents
where the woman has a mitochondrial defect would be for in vitro fertilization followed by transfer of the fertilized
nucleus to an enucleated egg from a healthy donor. Thus the embryo would have
three parents, the male and female who contribute the nuclear genome and the
female who contributes the mitochondrial genome.
It is hard to argue with the use of
mitochondrial replacement to prevent the passing of defective mitochondrial
genomes to children. In the current situation women who know they posses such
defects must choose between refraining from having children or passing their
defects to their offspring. However, if this approach is to be approved by the
FDA it is important to go forward with the understanding that it will open the
door to widespread use in other contexts. Mitochondrial transfer will become
yet another tool in the growing armamentarium of human enhancement
technologies, where advances made in the name of disease treatment are
subsequently applied to enhance the physical or cognitive abilities of healthy
individuals. A possible additional use is improving success rates for older
women during in vitro fertility treatments.
Beyond that application looms a whole range of other possibilities. The most
obvious, given the connection between mitochondrial energy generation and
muscle function, is to seek to enhance the athletic prowess of offspring.
Sequencing mitochondrial genomes is trivial with current ‘deep sequencing’
machines and it would be quite easy to sort through the mitochondrial genomes
of thousands of individuals seeking genetic patterns associated with
outstanding athletic capabilities. The ethical and societal implications of
such efforts are very hazy, but what is clear is that it will happen if given
the chance.
http://www.nytimes.com/2014/02/24/opinion/genetically-modified-babies.html?action=click&module=Search®ion=searchResults%230&version=&url=http%3A%2F%2Fquery.nytimes.com%2Fsearch%2Fsitesearch%2F%23%2Fmitochondrial%2BDNA%2F
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