Apr. 15th, 2010

catsittingstill: (Default)
There is an interesting article here.

The gist of it is that it appears to be possible in humans to produce an embryo from egg DNA, sperm DNA and an egg emptied of DNA that acts as a mitochondrial donor.  Mitochondria are little organs (organelles, actually) in the cell that "breathe" oxygen to produce energy for the cell.  If your mitochondria aren't working right you fall over and die for lack of energy.  (Sometimes the falling over and dying is prolonged long enough for people to actually figure out what is *wrong* but right now there isn't much that can be done.)

Mitochondria are not built by the cell, the way ribosomes and centrioles and stuff are--they act like little living creatures inside the cell, reproducing by fission (they split down the middle, like bacteria.  They're about the same size too.  This is not a coincidence).  They even have their own little circles of DNA (like bacteria), though a lot of their genes have gone to live on the cell's main chromosomes.  It is thought that mitochondria are the degraded leftovers of some free living bacterial cell that either invaded or was engulfed by another cell back when the first eukaryotes were starting up and instead of getting eaten by the engulfing cell, somehow switched tracks to live inside it for mutual benefit.  Normally mitochondria and maternal DNA come as a package deal, both in the egg.

Remember the multicellular life I was squeeing about last week that doesn't need oxygen?  That's because it's using something different for mitochondria (or arguably some very different mitochondria--I'm not sure anyone has investigated that closely enough to be sure).

Since some kids die young of diseases of the mitochondria, and this development, if it works out after much testing, might make it possible for would-be parents who were likely to have kids like this to recruit a donor to provide healthy mitochondria, it looks like a good, happy development to me.

But the article keeps saying there are ethical issues.  I'm sorry, I'm not seeing any ethical issues to speak of. 

Questions about who is a parent?  Don't we have those now?  Surely we have all kinds of people who walk the grey line between "genetically related *and* principal caregiver" and "not involved at all."  We have sperm donors, egg donors, surrogate mothers, step parents, adoptive parents, noncustodial parents, and parents who abandon, or regretfully give up, their children.  Now we'll have one more class: mitochondrial donors; why is this some sort of daunting problem?

One technique needs human eggs, which are uncomfortable and potentially risky to gather (I think because the long term effects of the fertility hormones on the egg donors are not well understood).  Well, okay, but we have procedures for making sure donors know what they are doing and consent without duress--why is this particular technique the one where those procedures don't work?

There might be risks not immediately evident--well, this is why we work such things out in laboratory animals before we use them in people.  And the first people will face risks that can't be fully known, which is the case with any medical advance, and we have procedures worked out for how we deal with that--why is this particular technique the one where those procedures don't work?

We're introducing a heritable genetic change?  I should hope to shout!  We're introducing a heritable genetic change that kids won't die young in exhausted misery; that's a good thing.

So, I guess, yes, I do see ethical issues; they're the same ones we've successfully dealt with in the past; we know how to do this, so why make a big deal out of it?

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