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Thursday, 30 June 2011
Mitochondria are bacteria that wandered into each of our cells about two billion years ago and set about making themselves indispensable.
They still reproduce separately from the rest of us, though. All your mitochondria came from your mother via her egg. They exist in sperm, too, and those sperm mitochondria enter an egg when it's fertilised, but then they are assassinated.
The mechanism of that assassination is superficially understood: ubiquitin is tacked onto the sperm's mitochondria in the egg, which marks their proteins for destruction. But as far as I have been able to find out, no one knows what it is in the egg that does the ubiquitin attachment.
I'd lay a hefty (well, a few quid...) bet that it is the egg's mitochondria that do the dirty deed. Look at things from the evolutionary perspective: the egg's mitochondria are in a secure comfortable environment with plenty of resources (a whole big egg) when along come some unrelated interlopers that will compete with them for lebensraum. But those interlopers are exhausted after powering a very long swim in a midget submarine, and their defences are low. Best exterminate them now before they recover.
And suppose some sperm mitochondria mutated to put energy into developing defences. Of course, their sperm would come last in the race as a consequence, so the forearmed mitochondria would never reach the egg in the first place.
The main nuclear genetic material in both the egg and the sperm have no dog in this fight - they don't care where they get their mitochondria from. So they look on dispassionately and don't take sides.
The trouble with this arrangement (from our perspective) is that mutations can accumulate in our mitochondria because there is no sexual combination going on to allow such mutations to be shelved as recessive and all the other shuffling advantages that sex confers. The results are many different types of mitochondrial disease such as early-age diabetes with deafness, various neuromuscular conditions (some fatal), certain epilepsies and - well; the list goes on.
What can we do? We can't attempt to give the sperm's mitochondria an effective defence against ubiquitination so that we all end up with two types of mitochondria from egg plus sperm, at least half of which ought to work. Any defence that we cook up will be at an evolutionary disadvantage for the reasons outlined above. It will not be evolutionarily stable.
Instead let's confiscate all the mitochondrias' DNA and save it as extra genes in our cell neuclei. Those genes would still build the protiens that would make mitochondria in our cells. But those mitochondria would have no genetic material of their own. They would just be a useful cell structure like many others.
Now, of course, those extra genes could have alleles, and could be equally inherited from both parents. This would allow much more variation and recombination than is possible with the - essentially bacterial - way that mitochondria reproduce at the moment, which in turn would make things far more robust and less prone to inherited disease.
Friday, 24 June 2011
The colder you are, the richer you are. The top map is world temperatures in 2007, and the bottom is GDP per person in 2006.
There are exceptions, of course. But they only go to prove the rule: the exceptions are hot places that are rich just because of natural resources (Saudi Arabia), or because they were very recently colonised by people from cold places (Australia).
We are tropical animals, so this seems strange. Surely, we would expect, our natural environment should be the one in which we should be the most productive? But the reverse is the case.
Those of us in the cold world carry a couple of millimeters of the tropics around with us all the time in the form of our clothes, and this gives us a clue.
Also, hot India is in the process of becoming rich, as is multi-climated China. Both are following on the heels of the now-rich Far East, which is also hot. Wherever the hot world becomes cold by the introduction of air conditioning, wealth follows.
The minimum you need to survive in a cold climate is food and shelter. But the minimum you need to survive in a hot climate is just food.
People have not evolved to be productive. Evolution doesn't care a hoot about GDP. People have evolved to survive with the minimum of effort in their natural environment. Out of it, they have to work harder. We don't need much in hot places, so we don't work hard there. The greater wealth in cold places is just a by-product of people needing to keep active and needing to be inventive to keep warm.
It is no accident that the Industrial Revolution was started by the manufacture of those millimeter-thicknesses of the tropics in a cold country.
Sunday, 19 June 2011
My late father once wrote a short-story in which the protagonist wore a hearing aid. The protagonist's hearing was fine, but he thought that the aid might make it even more sensitive than that of his unenhanced ears. In the story the idea didn't work very well, and I suspect that that would also be true in real life - it would certainly be a simple enough experiment to try.
About six years ago there was a minor (which is to say widely e-mailed then forgotten) fuss about Jie-jie shown above, who was born with three arms. Neither of his left arms was fully functional, but they had such similar - if partial - abilities that there was a long debate about which to amputate. At the time it seemed to me rather sinister (there's a joke for the Latin-literate in there somewhere) that no one involved was strongly advocating leaving both of them alone on the basis that one good arm plus two partially-functioning ones might be a lot more useful than one-and-a-half in total.
I was reminded of this when I dug my father's story out. There is a lot of work being done on artificial arms for amputees. These arms are powered and active, being controlled by nerve impulses that would be sent to the real arm if it existed. And they can be given abilities that no real arm has, such as continuous rotation at the wrist, or a multimeter wired into the finger and thumb, so the owner can analyse working electronic circuits.
Why not develop these for the able-bodied too? They have fully-functioning nerve signals that can be tapped for control, and it should be reasonably straightforward to separate the signals for the real arm from those for the fake: all that's needed is the equivalent of a shift key - something like curling up one's little finger would do.
We would all be more dexterous with an optional extra arm strapped to our shoulders...
Friday, 10 June 2011
Talking of Sherlock Holmes in my last blog post reminded me: I think I discovered the other day where his and John Watson's names may ultimately come from. Roger Johnson, the Press and Publicity Officer of the Sherlock Holmes Society of London says that, '...in the first draft, the characters were called Sherringford Holmes and Ormond Sacker. Sherringford was soon changed to Sherlock because Doyle ran 30 runs against a bowler named Sherlock at a cricket match and had "retained a certain fondness for the name”. Sacker became Watson and the first story was published in Beeton’s Christmas Annual.'
I would not presume to dispute so distinguished a Holmesian - I am sure that what he says above is Arthur Conan Doyle's true account.
But Conan Doyle may not have consciously known his real source.
Daniel Defoe wrote a pamphlet entitled A True Relation of the Apparition of One Mrs. Veal the Next Day after her Death to One Mrs. Bargrave at Canterbury the 8th of September, 1705. This is a ghost story; indeed it is one of the very first written short stories of any kind. It is only 15 pages long, but in it there appear both a Dr Sherlock and a Captain Watson.
Conan Doyle was famously interested in spiritualism, so it is highly likely that he would have read this pamphlet during his researches into that world. The pamphlet was written the best part of 200 years before Sherlock Holmes was created.
The names must have stuck in Conan Doyle's mind.
The distributors of e-books and the manufacturers of e-book readers wax long on the foolproof digital rights software that they incorporate to prevent users copying book files between each other. But the great strength of the electronic ink that e-books use - namely that it works by reflected light, making reading comfortable - is also a great weakness. You can put an e-book in an ordinary scanner and take the text straight off the screen.
Above is a scan at 600 dots-per-inch from an e-book. I ran it through gocr to extract the text:
Sherlock Holmes swallowed a cup of coffee, and turned hi_ attention to the ham and eggs. Then he rose_ lit his pipe, and settled himself down înto his chair. I'll tell you what I did first_ and how I came to do it afterwards_ '' said he. ''After leaving you at the st8_on I went for a charming walk through some admir8ble Surrey scene_ to a pret_ little village called Ripley_ where I had my tea at an inn, and took the precaution of filling my nask and of pum'ng a paper of sandwiches in my pocket. There I remained until evening, when I set off for Woking ag8in_ and found myself in the high-road outside B_8rbrae just after sunset. Well_ I waited until the road was clear-it is never a ve_ frequented one at any time, I fancy-and then I clambered over the fence into _e grounds. '' Surely the gate was open.! '' ejaculated Phelps.
That was with the program running its defaults and not tuned to, and taught, the e-book's font. Neither was it run through a spell-checker. If one did all that the result would be even better. Put a couple of wires into the e-book's next-page button and solder a MOSFET across them driven by one bit on the scanning computer's parallel port, and you could scan an entire book to text completely automatically...
Thursday, 9 June 2011
Some time ago I blogged about clothes that sweat for you. Feet are notoriously sweaty, and this is compounded by our habit of stuffing them into shoes. Despite the best endeavours of manufacturers to make shoes that allow moisture out but prevent rain coming in (like Goretex), most footwear tends to hold the sweat in, with malodorous consequences.
What's needed is some sort of wick and some sort of ventilation. But we already have both: socks and sandals. The only trouble there is that the combination, though intensely practical, is regarded as a fashion faux pas on a par with wearing wellies and a swimsuit to the opera.
Suppose we keep the socks and do something else for the ventilation? Specifically, suppose we put little air pumps in the shoe heels so that every step blows a puff of air in at the toes, which then flows up and out at the ankle taking the evaporated sweat with it.
Cool fresh feet, and the more you walk, the cooler and fresher they become...