With todays new's that the UK House of Commons has passed a bill by a majority of more than 3:1 to allow a form of in vitro fertilization to include mitochondrial replacement in cases where the woman is a carrier of mitochondrial disease, I thought it might be worthwhile looking at the cell organelles called mitochondria and how they and the diseases they can cause fit into biological evolution, and how poorly they fit into intelligent design, especially intelligent design by a benevolent and omniscient designer.
In effect, this bill will allow for three parents - one for the egg or ovum, one for the sperm and one for the mitochondria. Quite how this conflicts with ethical standards is beyond me and any notion that it is somehow immoral was rejected by three quarters of MPs who voted and of those who opposed it, most did so on grounds of clinical safety, not on ethics. Of course, there were a few religious fundamentalists who rejected it because they believe their god actually wants children to have mitochondrial disease but, in the context of UK politics, where spouting religious bigotry of that sort outside Northern Ireland is a quick route to the Job Centre, these objections have to be wrapped in a pretense of Humanist concern. The bill needs to pass through the House of Lords where no doubt the unelected, unaccountable Anglican bishops who sit there by right will have their say but there is hope that they won't be able to hold progress back.
The reason why a third, mitochondrial, donor is needed is because mitochondrial disease is (normally with rare exceptions) due to a mutation in the mitochondrial DNA, which is confined to the mitochondria and is not part of the nuclear DNA.
There are no mitochondria in the head of the sperm which enters the ovum at fertilization so all the mitochondria come from the mother. Fertilization is only concerned with nuclear DNA. In effect, the mitochondria are a clone of the mother's mitochondria, which is why we can use them to identify female lines of evolution and the origins of female populations. Scientists can now remove the defective mitochondria and replace them with normal ones.
|Turning glucose and ADP into CO2, water and ATP. |
How I remember writing this diagram out over and over until I learned it by heart.
This processing of basically stored sunlight energy in glucose to power the cell's metabolism is how living organisms can resist entropy and increase their organization locally according to the Second Law of Thermodynamics. The increase in entropy occurs ultimately in the sun, so there is no contravention of the Second Law, contrary to what creationist pseudo-scientist frauds tell their scientifically illiterate dupes.
Why do mitochondria have their own DNA? Because they started out as free-living prokaryote organisms which then entered other free-living prokaryote organisms, probably initially as parasites, then, as with all successful parasites in the long run, they became symbiotic. They may not have been the only prokaryote cells to do this. Some people have suggested that most eukaryote cell organelles started out that way, so eukaryote cells, from which all multicellular organisms are made, are derived from colonies of prokaryote cells. Most of these will have contributed their DNA to the cell nucleus and given up carrying their own, in a loss of complexity frequently seen in parasites. For some reason, mitochondria have retained most of their own, although they do get a few of their essential enzymes from nuclear DNA.
This colonization of prokaryote cells was probably the major significant event in the evolution of life on Earth and certainly took a long time to evolved. From the first signs of life on Earth some 3.5 billion years ago, it was to take about 2 billion years to evolve multicellular organisms. All the higher life forms have evolved in the 1.5 billion years since, and most of the basic metabolic processes, including the flagella evolved in prokaryote cells over those 2 billion years. The chloroplasts in green plants are another example of this colonization, this time by cyanobacteria.
But, as we would expect of any evolved system, things can and do go wrong, hence we have mitochondrial diseases caused by simple mutations or copying mistakes in the DNA which can disrupt the production of ATP for the cell, or reduce the efficiency of it's production. The explanation for this, the existence of mitochondria and the existence of mitochondrial disease, fits like a hand in a glove into neo-Darwinian Evolutionary theory, but how does it fit into the notion of intelligent design by an omni-benevolent, omniscient designer?
Well, according to fundamentalist Christian and scientifically illiterate creationist, Ray Comfort, his malevolent, intelligent, omniscient and evidence-free god wants children to be born with mitochondrial disease just as it wants them to have bone cancer, to become sex slaves or to be killed in natural disasters - because it loves them! This is so they can suffer to teach us a lesson for being born with the 'sin' it arbitrarily assigned to humans and decreed that we are born with. There is nothing we can, or should, do about it because, since his god designed it that way and wants children to suffer, this must be a 'good' thing. Anything Ray Comfort's 'intelligent designer' does is 'good' by definition. Suffering children is supposed to teach us to love this god and accept that we don't know right from wrong and need it to tell us.
You read that right - Ray Comfort's god, in common with the god of other creationists, the god of Christianity and the god of Islam, makes children suffer and designed genetic defects to remind us that it is the arbiter of right and wrong and the source of all morals. It created evil to show us how good it is and to remind us how much it loves us! To make the facts fit their notion, we need to redefine the word 'benevolent' so it includes mendacious, capricious, sadistic and vindictive.
There is no biological basis for this perverse and reprehensible philosophy, though creationist pseudo-scientists will try to force-fit reality into their obscene creed to fool their dupes and keep them sending them money, but this unmodified notion comes directly from pre-wheel, Bronze-Age, Middle-Eastern goat-herder and hill farmers from a time when there was minimal scientific understanding of the world and when the world was believed to be flat, at the centre of the Universe, and to run on magic. Like a Terry Pratchett SciFi novel but without the Humanism.
Ray Comfort and other proponents of this hideously creed 'know' it to be true because it says it in the book these goat-herders wrote and the book says it's all true. And that's it! No other evidence is needed so none is offered. And no other book can be allowed to contradict it because you can't rely on information in books and anyone who says otherwise must be defective in some way - and the cause of childhood disease. Ray Comfort famously banned a lot of people from his Facebook page for calling him a bibliophile. I can see his point; he's certainly no bibliophile.
[Update 25 February 2015] The bill to allow this technique was approved by the Upper House of the UK Parliament (The House of Lords) yesterday and now only needs the formality of Royal Assent to pass into Law in England & Wales, and Scotland. The UK is the first country to legalise this medical technique. It's use will be regulated by the independent Human Fertilisation and Embryology Authority which licenses and supervises clinics offering IVF services to ensure compliance with clinical, ethical and legal standards.
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