[Crossposted from GeneticFuture.org]
Scientists at Newcastle University have been given approval for new research aimed at combating a particular set of inherited human diseases: those that are passed on via mitochondrial DNA instead of the nuclear DNA most folks are familiar with. The trick? They’ll be creating human embryos that are the product of two mothers and one father. Here’s the background:
Nuclear DNA includes thousands of genes, and is given credit for making you who you are, and is in fact the only DNA considered when discussing the human “genome”. Mitochondrial DNA (MtDNA) only has 37 genes and doesn’t change much from individual to individual. However, that doesn’t mean that MtDNA isn’t capable of expressing diseases of its own.
So if you’re a mom who suffers from a mitochondrial disease, how do you keep from passing it on to your baby? According to the Newcastle researchers, here’s what you do: extract healthy ooplasm (including MtDNA) from a different mom’s egg cell and insert it into one of your own egg cells. Then fertilize it with the father’s sperm in the usual way (with glass rods and tubes and such) and presto! Healthy baby.
Trigger-finger ethics watchdogs suggest that you’ve just broken a new taboo — making an embryo that has two moms and one dad. Supporters would respond by saying that the nuclear DNA is the only “important” DNA, so who cares if the mitochondrial DNA comes from someone else?
Myself, I’m on the fence with this one. Most people would agree that there’s something ethically suspicious about making better babies by combining nuclear DNA from two moms. And while mitochondrial DNA doesn’t obviously code for things like blue eyes or long limbs, it does interact with nuclear DNA, working together for the expression and use of certain proteins. Will we discover some day that the rare and small differences found in MtDNA somehow have subtle (or profound) effects on the human phenotype — who we are and how we behave? If so, then mixing one mom’s DNA with the another mom’s MtDNA could lead us into ethically uncertain waters.
On the other hand, why not go for broke? Let’s use a surrogate mother for the womb too. Then we’ll have three mothers involved in the production of a newborn! Just imagine the positive impact such practices could have on profits on Mother’s Day…
[ Reference: BBC News ]