Slashdot Mirror
Study Detects Recent Instance of Human Evolution
The New York Times is running a Sunday article regarding new evidence about 'recent' human evolution. A research team at the University of Maryland has done some work looking at the rise of lactose tolerance in the human populations of Africa. From the article: "The principal mutation, found among Nilo-Saharan-speaking ethnic groups of Kenya and Tanzania, arose 2,700 to 6,800 years ago, according to genetic estimates, Dr. Tishkoff's group is to report in the journal Nature Genetics on Monday. This fits well with archaeological evidence suggesting that pastoral peoples from the north reached northern Kenya about 4,500 years ago and southern Kenya and Tanzania 3,300 years ago ... Genetic evidence shows that the mutations conferred an enormous selective advantage on their owners, enabling them to leave almost 10 times as many descendants as people without them. The mutations have created 'one of the strongest genetic signatures of natural selection yet reported in humans,' the researchers write. "
I realize that this is popular press and all, but why is mutation always mentioned, but crossover, never so?
Generally speaking, mutation is almost always fatal, crossover is almost never so. Crossover keeps you "in the genome", where mutation is just as likely to kick you out of it. My own theory is that mutation is the driver behind speciation, while crossover is the driver behind evolution.
I've run lots of GAs with mutation turned off, letting crossover do all the work. Crossover, not mutation, is what lets a population do that slow walk/hillclimb, over time, through the genetic landscape.
No folly is more costly than the folly of intolerant idealism. - Winston Churchill
Unfortunately this will prove to be an evolutionary dead end, as these genes will never be passed on.
Home fucking is killing prostitution.
And it gets modded up.. As insightful at that.. :( Sigh. Note to the OP i don't have anything against you but I wish you wouldn't generalize. Feel free to make fun of the "crazies". It's okay. But don't bring Jesus into stuff like this. He didn't say anything about this kind of thing! His whole existance on this Earth was to set an example as to how we should behave and to give our lives meaning.
I think this is an awesome find. Cool. I look forward to more. Guess what I'm a Christian and obviously believe in Jesus.
As I post in all these threads: I'm for gay marriage, pro choice (though anti abortion I don't feel I can make the choices for others), for legal gambling (we don't live in a theocracy), pro legalized drugs and prostitution (what do you think Mary Magdalene was???) etc.
Slashdot would be a wonderful place if we could lose all the religion bashing.
People on the fringes don't speak for all of us. I don't try to force my views on others. I interest my friends in learning more about my views by: being nice to them and treating them well, and listening when they have problems and trying to help them out whenever I can.
Did you know that if, today, you went and tried to translate the original Genesis story into English today it could have 4 or more meanings? The Bible you read is the most *probable* meaning but it is NOT the only meaning that Moses could have intended when writing it.
Seriously, evolution happens all around us. We know. However, it doesn't necessarily mean God didn't put us here, or any of that Jazz. In fact the two don't really have anything to do with each other at all. The fossil record DOES show species just "appearing" as if they were just created. It also indicates that the Earth is very old. So what? That just indicates that: we have more stuff to figure out about our world. We discover stuff that was previously unkown all the time. Cool. I believe God gave us our mind so we could do as much as we can do understand the world around us. Are we always going to be right? No. But that doesn't mean you are a "dirty sinner" or something if you are.
Humans don't have a full understanding of everything. I'm cool with that. I look forward to learning more about evolution. As we learn more and more about the detail of the universe I think it shows us more and more about how awesome God is for putting it into place.
replacing it with NEW Folger's Crystals! (lets see if they notice the difference)
Being able to digest milk can be incredibly valuable in an environment where protein and many other nutrients present in milk are scarce (a fair assumption regarding conditions a couple of thousand years back).
But yes, of course smarts can pay off to various degrees in Darwinian terms too, depending on what niche you are looking to fill.
It's not actually that simple. For example, the increase in height in Westerners isn't micro-evolution it's simply diet. When man went from hunter-gather (the state to which we evolved), to an agrarian lifestyle, the quality of diet went down, it hit rock bottom in Europe in the middle ages where teh majority of the population were quite severly malnourished and therefore short. The heights we are currently reaching (pun intended) are basically those of our hunter-gatherer forefathers, because as a population the quality of our diet over the last 50 years has improved so much. Of course we're probably heading down the path of too much now...
So my point is, that it's not easy to define or prove 'micro-evolution'. Just to clarify, I am a biologist by trade and am quite comfortable with the punctuated-equilibrium model of evolution, I'm certainly not arguing that evolution doesn't happen, just that we have to be careful with our conclusions.
Si hoc legere scis nimium eruditionis habes.
Because you're far more likely to survive the couple of millenia between domesticating cattle and making your first gun if you can tolerate lactose.
Mmmm... I think saying "I really don't think" is quite honest of you, although it is already painfully obvious to most of us here.
Humans originally didn't have the enzymes to digest cow lactose; why should they? It serves no purpose in a hunter-gatherers genome.
Most infants can digest lactose well enough to get by as they are expressing genes at that age to aid in the digestion of human milk, but by age 5 cow milk normally makes a lactose intolerent person puke mucus.
Occasionally through mutation some did have the right enzymes to digest cow lactose through adulthood, but as humans did not keep cows those people had no advantage over other people without the mutation, so the mutation was lost as it had no benefit.
When humans started to keep cows they had access to a new food source, milk.
This would have been used to feed infants to replace or suppliment the mother's milk, probably as part of the weaning process.
As those infants grew older those with tolerence to lactose had access to a renewable food resource denied to those who were intolerent to lactose. Those lactose intolerent infants whose parents kept feeding them milk would have been sickly and malnourished.
There would be such a big ebenfit to lactose tolerence that somethng called 'runaway evolution' took place. It's a bit like how mudskippers evolved; if ten fish of a species in a river survive a drought survive because of x charecteristics only they (in that species) have, after that drought all members of that species have x characteristic.
Similarly with human lactose tolerance the stronger, better fed, healthier members of the population with lactose tolerence would have had way more offspring then those who didn't have the genes for it, and those offsrping would fare better.
If 5% increase in genetic transfer through natural selection can make a new characteristic spread throughout a population in less than 200 generations, think how more quickly one with a much higher advantage might spread.
Guns are part of an extended phenotype, and are NOT subject to genetic transmission. Idiot.
Touch the monolith, monkey boy.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
You're far too reasonable, I don't think you'll like it here.
Erm. You're confusing general lactose intolerance with adult lactose intolerance.
General lactose intolerance is a bad thing. Any mammal that doesn't tolerate lactose while still nursing is in very deep doodoo. It's a mutation that'll basically kick you out of the gene pool immediately.
Adult lactose intolerance is, for most mammals, a normal thing (which is why you shouldn't give milk to cats/hedgehogs/etc). Adult mammals aren't supposed to seek out sources of milk, for obvious reasons, which is why the production of lactase usually stops once the mammal is old enough to eat real food. Of course, this mechanism evolved loooong before humans got the idea of domesticating goats/sheep/cattle and use the milk of a completely different species to supplement their diet. This made a mechanism that would have been faulty (adult mammal that tolerates lactose) suddenly become a genetic advantage.
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
I'm not the original poster, but as I seem to have similar opinions, I'll bite.
First off, the law in the Bible has always been for the people of God. In the Old Testament, that was the Jews. After Jesus, it expanded to include Christians. Nowhere in the Bible does it say that non-believers should be made to follow the law (In the OT, the Jews were told to kill certain unbelievers, and in the NT Christians are called to convert them, but they're never told to force them to follow the law). Biblically, you don't get saved by following the law (or rather, you would, but nobody ever manages to keep it 100%). You get saved by following Jesus. Going around forcing people who don't follow Jesus to act as if they did accomplishes nothing except to get them really annoyed. It's not going to save anyone, and it's counterproductive.
Since, as the grandparent said, we don't live in a theocracy, the government should not necessarily be bound to obey the laws of God. I believe homosexuality is wrong, but I believe the government shouldn't be making laws about morality. Governments should make laws to provide for the security and freedom of its citizens - anything else is (or should be) out of its scope. If it's an issue of morality, then it should be in the hands of the church (as the rules of the church apply only to its followers). So allow gay marriages - as long as you don't force me to partake in one, or force my church to officially sanction it. Allow prostitution and drug use - as long as you don't force me to foot the bill to treat the addicts, or allow people to use being "under the influence" as a means to escape their actions. These are consensual activities, and are issues purely of morality, and should not be prohibited by the government. As long as the government doesn't stop me practicing my religion, it should allow everyone else to do whatever they like, as long as it does not significantly impact other's freedom or security.
On the other hand, things like murder, rape and theft have an impact on the citizen's freedoms and security. The government should forbid them. The current abortion debate (and the therepeutic cloning debate) are essentially a definitions debate, determining when a developing human should be given the same protections as a fully developed human.
As an aside, Mary Magdalene wasn't a prostitute - Rahab was though, and she was judged as righteous. Not because of her profession, but in spite of it. The Bible isn't defending prostitution as a moral choice, it's saying nobody (including prostitutes) is beyond redemption.
Just because you're paranoid doesn't mean there isn't an invisible demon about to eat your face
I read the article, I'm not the Breast Surgery Chief but I do have a fairly solid background in biology. The thing that made my bullshit meter go into the red is when he tried to discredit pasteurization. Also, he uses very weak arguments and then doesn't back them up. You can't just say milk has bacteria, bacteria makes people sick, therefore milk is bad ... it's simply too broad a brush to use in biological terms. If you want to talk about scary stuff, look at all the recent fecal coliform contaminated vegetables in this county. If this author took a stance on that subject, it would read like this: fertilizer and reclaimed water used to irrigate vegetable fields contain fecal coliforms, fecal coliforms make people sick, therefore vegetables are bad. Disconnected facts do not an argument make.
Good people do not need laws to tell them to act responsibly, while bad people will find a way around the laws-Plato
I just wanted to add a note on the milk digression, I suppose. There are huge nutritional differences between pasteurized and raw milk, in terms of health benefits to humans. The live enzymes present in raw milk (phosphatase for cascium absorbtion, lipase for fat digestion, lactase/-ose, galactase/-ose, catalase, diastase, peroxidase, etc) are destroyed to a large extent by the pasteurization process. In raw milk, all 22 amino acids are present as well, whereas in pasteurized milk, the polypeptides lysine and tyrosine are changed by the heating process such that they are not as easily metabolized (meaning your body can't use the proteins as readily or as easily). Vitamins A, F, E, and D are lost to a large degree by the heating process as well, as is Vitamin C (though to a lesser degree). B6 and B12 are pretty much destroyed all together. Also, raw milk is seriously tasty. If you ever to a taste comparison, there's really no contest. It's a full, earthy flavor, whereas the flavors of pasteurized milk and milk products are shallow and less complex. Obviously, drinking raw milk has its risks. It's important to know where your raw milk is coming from and the process by which it's being produced. If the cows are fed what cows are supposed to be fed (grass, pasture plants, etc) and if the conditions on the farm are clean and natural (no anti-biotics, no hormones, no cows being fed other cows, no over-crowding), there shouldn't be a problem with pathogenic bacteria in the raw milk and it should be safe for human consumption. The beneficial bacteria, as the dominant culture, will prevent the growth of harmful bacteria (whereas in pasteurized milk, a sterile medium, there is no active culture of good bacteria to prevent bad bacteria growth). Going to the farm yourself is the best bet, although there are many states in which it's illegal for farms to sell raw milk due to the risks involved with sub-par milk production (factory farms, etc) and so raw milk purchases, even at all-natural organic farms, have to be made rather on the down low. It's good, though, for people to be involved more in their food, to know where it's coming from, to take an active role in their health and diet through awareness of the production process and its results. Also, a last thought: I don't think that relying on milk as a sole source of calcium would be good, but then, relying on any one thing for nutrition is probably not wise. Moderation and diversity are most likely the best routes to take. Go team Human.