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Furthermore, similar evolutions can happen multiple times. For example, a group of sparrows might grow longer beaks, then shorter beaks over time as their available diet changes. Indeed, we know such things have happened in the past to hominids.

They found a jaw bone. Jaw bones aren't very complete evidence, especially given the number of fossils found actually within Africa.

OTOH, if you want to find subversive text in all this, I find it a little bit racist to refer to her strictly as a "black" woman, when clearly she's extremely light skinned and only lightly exhibits the typical facial features of african heritage (which is a real thing before the SJ kneejerkers scream racism: http://johnhawks.net/explainer... , as did her parents, which strongly suggests a white lineage as well.
This doesn't matter academically of course, she did what she did because of who she was, not what she was, but why is it if someone has half, or even just 25% african heritage in the US, they're still typically considered simply "black' for all intents and purposes, and it's as if the Caucasian or Sino-Asian heritage is submersed and dismissed? Both Halley Berry and Obama, for example, are equally half white/black but they're flatly considered black by most accounts. Obama was even raised by his US mother and her parents, who were white. Few other than Morgan Freeman seem to comprehendf that Obama is actually 50/50.
This can work either for or against someone actually (as in the case of Obama, supporters and detractors alike), but why don't we just honestly refer to mixed race people as mulatto anymore, or maybe "mixed", when that's the simple truth of the matter?
It seems rather belittling to both races: the white aspect is ignored, and the black aspect is patronized, as the parent post pointed out.

Apes does not equal hominoids. If it did, it would be a cladistic term, and it isn't.

Humans are not apes, not by any historically common definition, nor by the definition used by palaeoanthropologists. In fact, "ape" is specifically used to distinguish humans from other hominoids (i.e., when you want to say "all the hominoids except humans", you say "apes").

You really should to a bit more research than simply typing "ape" into Wikipedia and seeing that someone merged two pages that they shouldn't have. Here:

http://johnhawks.net/weblog/topics/phylogeny/taxonomy/humans-arent-apes-2012.html

But hey, what does a guy whose job consists of classifying humanoid species know about it, right?

It's kind of sad that Slashdot "moderation" these days seems to consist of "Did he post a link to Wikipedia? Then it's an 'insightful' post!" It just reinforces self-righteous ignorance.

I'd feel much better about believing you if your source material wasn't well known for being, shall we say, exaggerated at times?

While there is no solid answer, you are arguing the wrong thing. Maximum age is not the same as "people not living as long". Lots of people died in their 30s, 40s, and 50s, making the few who lived to the natural old age death were few and far between.

Here is an article which is attacking a Live Science article, and hopefully you can make the distinction. It argues your point, more or less. Evaluating both articles should prove enlightening.

The statement still stands - people didn't live as long. If you like, take a hypothetical population of 100 people, assign the life expectancy to each member of the group, and see when they die. Count the number of years lived, and you have fewer total years in the lower life expectancy group - despite similar maximum ages.

I will say that it wasn't so much pressure to breed - that is probably overstatement. But the accepted age of motherhood certainly was younger when lifespan was shorter.

That's the 'noble primitive' myth. It's only a myth.

I wasn't talking about the idea that people in smaller tribes were inherently more moral people (which is what the noble primitive myth deals with), but that crime is low because of social pressures in small groups (where everyone knows everyone, and it is harder to get away with crime) or for other reasons. My point was that crime rate is smaller in a smaller social group, but more and more people prefer to live in/around cities.

depends on the type of crime, i guess.

i know that at least homicide is much lower in today's "western" society (about one in a hundred thousand per year) in comparison to contemporary hunter-gatherer tribes (one in a hundred to one in three thousand).

"All the time" ... Observed how?

Examples include trisomy, insertions and gene duplication.

In short, no, human mutation rate was not measured. They compared human and chimp genomes, assumed the difference is due to evolution and then treated that difference as the human mutation rate using dates derived from evolutionary assumptions. Exactly what you just said before in summary, which I challenged for being circular when used as a rebuttal to my challenge.

Point taken. So, start here, then(a good overview of precisely the mistake I made). The lowest estimated mutation rate based simply upon human genomes is 1.0 x 10-8 per site per generation. Still the same order of magnitude, so it won't have a substantial effect on my point.

Read this and question for a moment the fallibility of human imagination.

And I suggest you read some of the comments by actual paleotologists on that page.

Then look at these two pictures and tell me why the concept art is "scientific" as opposed to "fantasy"

Because we also have fossils of the related species as well, which gives us a good idea of how the intermediate species will look. But, then, judging by your later comments, you've already decided that physiology can't be derived from fossil records, so I wouldn't expect it to matter.

See, if evolution is true, then there's no reason why we can't one day reverse engineer DNA completely (hey, it's random and we're semi-intelligent). At that point in time, we can create any arbitrary DNA sequence, and should be able to reconstruct the intermediate life forms from the DNA sequences. If it happened once by lucky circumstances, we can do it again, intentionally.

And why would you assume that? We could create a lookalike, but we will never know if we got all of the genes correct.

In short, there's nothing in natural selection that can select against specific base pair mutations. Natural selection can't select for the future, it only compares against now.

Of course.

Not by natural selection based on overall fitness, but by highly specific genetic "error-check" systems (against what reference?).

What are you talking about? I am talking about death. An organism with a broken metabolism won't survive past a single cell stage. An organism lacking cellular adhesion would not survive past that stage. No "reference" involved at all. Things that are broken just die.

Now how did natural selection work *before* that system evolved into existence, and where is your evidence that life works without it? (Even "basic" bacteria have this functionality)

Early life would have had more errors in transcription, which is exactly what we would expect. Later, as gene expression became more robust and complicated, selection pressure would increase for less error prone mechanisms.

It was a starting point to illustrate the enormity of the problem

And, as I pointed out, you ignored the reality of the theory in order to artificially inflate the problem.

This is part of why I don't consider evolutionary theory to be "solid scientific fact" as you do - it fails to do rigorous mathematical modeling. If it is so plausible, there should be math that puts my rough model to shame; and yet I haven't seen anything that attempts to capture the probabilities involved or how evolution comfortably meets the challenge.

That is because you are starting off from a bad theoretical foundation and expecting th

If you go look at my original post, I was actually just pointing out that a man's age contributes to birth defects just as a woman's does. I was willing to be drawn into this aside, though, because it's a fascinating topic.

In my reading, modern scholarship indicates that ancient people mostly died in their thirties, though some - mainly the very wealthy - did live what we would consider "full" lives. I am more inclined to believe the forensics than ancient record keeping; it is the latter that tends to present evidence of "old ancient people."

It's a controversial area, which does not even touch upon the idea of an evolutionary - that is a biological - impact on the species.

Here are some links I came up with (representing an array of reasonable views):
Tables of ancient life expectancies, with sources.
Review of studies finding "old ancient people."
An archaeologist's blog post discussing this issue.
Roy. Soc. Med. paper finding "old ancient people".
The wiki entry, with lots of information and sources.
A PNAS paper which actually discusses population ratios - very interesting.

Yes, they definitely extracted mitochondrial DNA (that's DNA that isn't in the nucleus but is rather in the mitochondria and is only passed down by your mother). Yes, the DNA looks different enough that they're pretty sure this isn't any form of contamination from modern samples (always a worry when doing this sort of thing). However, it is far from clear that this DNA is belonged to another species. There are multiple possible other explanations which could make this not another species. The details are a bit technical, but anthropologist John Hawks has a piece on his blog laying out the basic issues- http://johnhawks.net/weblog/reviews/neandertals/neandertal_dna/denisova-krause-2010.html. A slightly more lay-oriented piece by Carl Zimmer (the writer for Science Times and author of the very excellent book Parasite Rex) is also worth reading: http://blogs.discovermagazine.com/loom/2010/03/24/the-x-womans-fingerbone/. The bottom line is that concluding that this is a new species is as of yet very premature.

Bunk. Utter bunk. This whole like of research was abandoned in the 1950s because it became evident that the "Boskop" skull was simply an unusual individual, possibly suffering from hydrocephalus (a condition where too much spinal fluid is produced, causing cranial overpressure and often an enlarged head).

The cranial volume of the skull is within the range of variation of the living human population. The volume is estimated at about 1800 ml, which is right in the distribution for male skulls.

And, in any event, it's been well established that there is no correlation between brain volume and apparent intelligence among modern humans (anyone alive 10,000 years ago is firmly in this category). For a detailed history of this quackery and hogwash, see Stephen Jay Gould's The Missmeasure of Man.

Didn't anyone bother to Google "boskop"?

He just ripped off John Hawks' blog posting verbatim:
http://johnhawks.net/weblog/reviews/brain/paleo/lynch-granger-big-brain-boskops-2008.html

Probably a spammer trying to build karma.

Just so people know, there is skepticism over the existence of some ancient race of geniuses based on this skull.

"The history of evolutionary studies has been dogged by the almost irresistible idea that evolution leads to greater complexity, to animals that are more advanced than their predecessor, yet the existence of the Boskops argues otherwise..."

Evolution does *not* imply that things ordinarily increase in complexity. They can do so, but there is no expectation that they must. Besides the fact that "complexity" is a fiendishly difficult thing to measure anyway, there are many times when "simplification" is more optimal, and "simplification" trends often show up over evolutionary history. "Simple" creatures are enormously successful today. If there is any trend to evolution, it would be more accurate to say that the "complexity" of creatures broadens over evolutionary history, with plenty of "simple" creatures living alongside more "complex" ones. Life diversifies.

Biological systems always involve tradeoffs, and while a larger brain in some environments might be of benefit, there would be associated costs (e.g., the challenges of maintaining bloodflow to that increased volume, greater difficulty of childbirth, slower development, etc.). Worse, because of the relationships between different systems during development (i.e. the growth that occurs from conception to birth, and even afterwards) tweaking the genetics of one feature might have surprising side-effects on other systems that could be undesirable. Maybe increased brain size didn't pay off sufficiently, or maybe the environment in which it did pay off went away over time, thus causing extinction of this variety. Finally, perhaps brain size decreased over recent human history because evolution has been simultaneously pushing brainsize to increase "intelligence" (whatever that is), while optimizing the way the brain works and other systems to be more efficient about it -- i.e. maybe it has tweaked things to get better intelligence out of lesser volume, thus lowering some of the costs of a large brain. A slightly smaller brain may be more optimal for the whole system.

All of this assumes that the original observation of "larger brain size" of these skulls is valid, which as other people have pointed out, it probably isn't.

http://johnhawks.net/weblog/reviews/brain/paleo/lynch-granger-big-brain-boskops-2008.html
 
  Full debunking of the Boskop bollocks.

Actually, the idea of a "Boskop race" or "Boskop Man" is long discredited. The hypothesis occurred by actively selecting the larger skulls from the available set, and misclassifying them as a distinct population.
It turns out that by examining the whole set of preserved skulls, cranium size distributions are similar in South Africa, Europe, and China for the period in question. Skulls of that era with rather large crania (comparable to the Boskop specimens) can be found in all regions.
Cranium size distributions are similar between those regions today also, but the distributions have shifted to slightly smaller sizes than they were around 10000 BCE (probably due to agriculture & civilization). http://johnhawks.net/weblog/reviews/brain/paleo/lynch-granger-big-brain-boskops-2008.html

in fact, what happened is that a small set of large crania were taken from a much larger sample of varied crania, and given the name, "Boskopoid." This selection was initially done almost without any regard for archaeological or cultural associations -- any old, large skull was a "Boskop". Later, when a more systematic inventory of archaeological associations was entered into evidence, it became clear that the "Boskop race" was entirely a figment of anthropologists' imaginations. Instead, the MSA-to-LSA population of South Africa had a varied array of features, within the last 20,000 years trending toward those present in historic southern African peoples. Singer ends his paper thusly:

It is now obvious that what was justifiable speculation (because of paucity of data) in 1923, and was apparent as speculation in 1947, is inexcusable to maintain in 1958.

That is pretty much where matters have stood ever since. "Boskopoid" is used only in this historical sense; it is has not been an active unit of analysis since the 1950's. By 1963, Brothwell could claim that Boskop itself was nothing more than a large skull of Khoisan type, leaving the concept of a "Boskop race" far behind.

So there you have it. There wasn't an extinct hominid with an IQ of 150, it was just the fallacy of selection bias exhibited by some anthropologists more than 70 years ago.

I have an FAQ up on my blog.

It gives some of the story behind the news, and delves into the anatomy and implications for hominin origins. I'll be updating it as the day goes on to add more information.

See, for instance, Hawks et al, 2007:
http://johnhawks.net/weblog/topics/evolution/selection/acceleration_embargo_ends_2007.html

Jones' theory appears based on his extrapolation of the genetic consequences of human mating customs. Hawks' theory is based on a large survey of linkage disequilibrium data.

Hawks' conclusion, after looking at the actual data, is that the rate of adaptive substitution in humans *increased more than 100-fold* within the last 40,000 years.

And actually, due to the methodology, that's a conservative estimate.

The PNAS paper isn't available to the public, technically. As the lead author, he could probably get in trouble for linking to an unofficial (non-PNAS) copy.

Not being under those constraints, I might point you toward this. He also has a faq up on his blog about the paper.

Just FYI, Hawks has an interesting blog at http://www.johnhawks.net/weblog

I think it's down right now, but I'd recommend it!

It amazes me that this kind of thinking gets anywhere at all.

Keep in mind that the media does a really poor job of reporting on scientific topics, and are often prone to sensationalist and simplistic interpretations. (Which can be blamed on poor reporting and the desire to make money by sensationalizing and "dumbing down" things for readers.)

The real story is that genetic analysis found alleles most concentrated in europeans that appear to have entered the gene pool around 37,000 years ago. The alleles, themselves, appear to be quite a bit older than 37,000 years. Since neanderthals were living in the same geographical area where we now find these alleles in humans, and because the timing matches up (humans and neanderthals both lived in europe 37,000 years ago) it's guessed that the human gene pool might've gotten these alleles from neanderthals. http://sciencenow.sciencemag.org/cgi/content/full/ 2006/1106/1?rss=1 http://johnhawks.net/weblog/2006/11/08#introgressi on_faq_2006

Here's some background that isn't apparent from the article. The CNN piece talks about Neanderthals in the context of understanding brain evolution, but the million dollar question- in most scientists' minds- is whether Neanderthals and early modern humans interbred, after 500,000 years of separation. It seems at least possible: lions and tigers produce fertile offspring and they diverged 2 million years ago. As the New York Times states,

        "A longstanding dispute among archaeologists is whether the modern humans who first entered Europe 45,000 years ago, ultimately from Africa, interbred with the Neanderthals or forced them into extinction. Interbreeding could have been genetically advantageous to the incoming humans, says Bruce Lahn, a geneticist at the University of Chicago, because the Neanderthals were well adapted to the cold European climate -- the last ice age had another 35,000 years to run -- and to local diseases.

        Evidence from the human genome suggests some interbreeding with an archaic species, Dr. Lahn said, which could have been Neanderthals or other early humans."

Now, nobody really knows much at this point. But something that I found interesting was that, via John Hawks, "Neandertals will be within the human range of variation for most genes." And the "pilot experiments" Rothberg mentioned is a reference to how their team sequenced the DNA of the cave bear as a test-run. As I understand it this was mostly to convince museums that grinding up some of their prize Neanderthal fossils in the name of research was a good idea. :)

John Hawks, a professor of anthropology, has a pretty sound and harsh refutation of the article. It looks like, if John is to be followed, that this is some pretty wishful thinking and sloppy work.

He has a follow-up post on his weblog as well.

John Hawks, a professor of anthropology, has a pretty sound and harsh refutation of the article. It looks like, if John is to be followed, that this is some pretty wishful thinking and sloppy work.

He has a follow-up post on his weblog as well.

John Hawks, a professor of anthropology, has a pretty sound and harsh refutation of the article. It looks like, if John is to be followed, that this is some pretty wishful thinking and sloppy work.

He has a follow-up post on his weblog as well.

..and someone better than me has already ripped it apart.

The parent post asks such great questions. I have a post on my blog about the fossils and what they may show about the biogeography of early hominids.

In response to the questions:

• the evidence for a "missing link" is not very convincing -- it is only "missing" in the sense that fossils at the same time had not yet been found in Ethiopia
• the idea of a link from Ardipithecus is convenient, since Tim White did find Ardipithecus
• The fossils do not show any particular transitional features between Ardipithecus and Australopithecus, nor would we necessarily expect them to since Ardipithecus isn't very different from Australopithecus -- the story they are pushing is the location.
• There are really only three partial sets of maxillary teeth, a part of a femur shaft, and some vertebrae and finger and toe bones. This isn't the next Lucy, in other words

In any event, please read my blog for more information; I always update when new fossils are found!

-John

The parent post asks such great questions. I have a post on my blog about the fossils and what they may show about the biogeography of early hominids.

In response to the questions:

• the evidence for a "missing link" is not very convincing -- it is only "missing" in the sense that fossils at the same time had not yet been found in Ethiopia
• the idea of a link from Ardipithecus is convenient, since Tim White did find Ardipithecus
• The fossils do not show any particular transitional features between Ardipithecus and Australopithecus, nor would we necessarily expect them to since Ardipithecus isn't very different from Australopithecus -- the story they are pushing is the location.
• There are really only three partial sets of maxillary teeth, a part of a femur shaft, and some vertebrae and finger and toe bones. This isn't the next Lucy, in other words

In any event, please read my blog for more information; I always update when new fossils are found!

-John

The parent post asks such great questions. I have a post on my blog about the fossils and what they may show about the biogeography of early hominids.

In response to the questions:

• the evidence for a "missing link" is not very convincing -- it is only "missing" in the sense that fossils at the same time had not yet been found in Ethiopia
• the idea of a link from Ardipithecus is convenient, since Tim White did find Ardipithecus
• The fossils do not show any particular transitional features between Ardipithecus and Australopithecus, nor would we necessarily expect them to since Ardipithecus isn't very different from Australopithecus -- the story they are pushing is the location.
• There are really only three partial sets of maxillary teeth, a part of a femur shaft, and some vertebrae and finger and toe bones. This isn't the next Lucy, in other words

In any event, please read my blog for more information; I always update when new fossils are found!

-John

...because I don't think there is any bird alive today that doesn't fly away the minute we get anywhere near them, no matter how large. (okay, maybe an ostrich will fight us, but that is a BIG bird...)

Certainly so, if it was big enough to carry the kid off -- we're talking about a 2-4 year old toddler -- it would have to be a LOTR-size eagle. Maybe Gandalf called in an airstrike?

I think either an attack with damage inflicted at the site of attack, or an eagle who had later access to a carcass killed by another predator and carried off only the head would be more likely hypotheses.

An earlier poster suggested that carrion birds might have been responsible, and I think that is a good idea as well.

This story is mostly old news; the same researchers proposed it about ten years ago. The original idea was that the site where the skull was found (Taung) had a lot of young monkeys, which not only suggests predation, but also a relatively lightweight predator. Most of the other South African caves preserve larger adult specimens as well, which might have gotten in themselves or been carried (or dropped) by larger predators like leopards. It is a very tricky case to say that the accumulating agent at Taung must have been eagles, though, since it is much more likely that different predators and non-predation factors operated at different times for any given site.

What they found that justified a new paper was damage inside the eye orbits of the specimen, which is one area where eagle talons damage their prey. It could be true, but on the other hand there is a lot of doubt. After all, eagles aren't the only predators that damage the eyes, and there are other ways that the bones may have accumulated, chiefly water transport, that might not require predation at all. As one of my colleagues put it, so many young primates die of disease or inadequate nutrition; the chances of this story is greater than zero, but how much?

Actually, the HapMap is basically useless for "rare" genetic variants, because it intentionally is screening for common ones. Hence, it may actually be useful for common susceptibility alleles for heart disease or stroke but it isn't going to find the rare variants that affect only a few people.

From my weblog:

The HapMap is an incredible step forward in characterizing human genetic variation. It's a challenging dataset to work with, though. It's like an old map showing continent margins and little else -- we can see many of the common SNPs, but for most we have no idea which ones are functional or what they might do.

It would not only have to be an australopithecine; it might have to be a DWARF AUSTRALOPITHECINE.

Consider that the femur length of LB1 is just a millimeter shorter than Lucy and its body proportions are basically the same. Lucy (AL 288-1) is not only the most complete known australopithecine skeleton (barring STW 573, which is yet to be described), it has the smallest limbs. There are some individual bone fragments with smaller dimensions than Lucy's, but not very much smaller. At the same time, there are many larger specimens. Some of these, like the Sibilot radius KNM-ER 20419, are a whole lot larger.

Now at Liang Bua, LB1 is nearly the biggest specimen. Brown et al. (2004) do report another radius from an older part of the deposit with an estimated length of 210mm. Again assuming the same brachial index, this would correspond to a humerus of 269mm, around an inch longer than LB1.

But the other two adult long bones reported are the LB6 radius (157mm) and the LB8 tibia. At an estimated 216mm, this tibia is substantially shorter than the 235mm LB1 tibia. There is no comparably complete australopithecine femur, but if Lucy (missing around a third of the shaft) was around the same length as LB1, then LB8 would be shorter than any australopithecine.

Even worse, it is shorter than all but one of 47 chimpanzee tibiae in my comparative data. That's really short.

That and other questions answered on my FAQ about the Flores fossils.

It would not only have to be an australopithecine; it might have to be a DWARF AUSTRALOPITHECINE.

Consider that the femur length of LB1 is just a millimeter shorter than Lucy and its body proportions are basically the same. Lucy (AL 288-1) is not only the most complete known australopithecine skeleton (barring STW 573, which is yet to be described), it has the smallest limbs. There are some individual bone fragments with smaller dimensions than Lucy's, but not very much smaller. At the same time, there are many larger specimens. Some of these, like the Sibilot radius KNM-ER 20419, are a whole lot larger.

Now at Liang Bua, LB1 is nearly the biggest specimen. Brown et al. (2004) do report another radius from an older part of the deposit with an estimated length of 210mm. Again assuming the same brachial index, this would correspond to a humerus of 269mm, around an inch longer than LB1.

But the other two adult long bones reported are the LB6 radius (157mm) and the LB8 tibia. At an estimated 216mm, this tibia is substantially shorter than the 235mm LB1 tibia. There is no comparably complete australopithecine femur, but if Lucy (missing around a third of the shaft) was around the same length as LB1, then LB8 would be shorter than any australopithecine.

Even worse, it is shorter than all but one of 47 chimpanzee tibiae in my comparative data. That's really short.

That and other questions answered on my FAQ about the Flores fossils.

The interesting thing about gorillas is that they make tools quite readily in captivity, but hadn't yet been observed to use them in the wild. This would imply that their toolmaking facility was not actually a product of adaptation for toolmaking in their natural habitat.

We could entertain a couple of hypotheses about this. Perhaps all apes share a common toolmaking ability shared from our common ancestors, which now is used in some lineages (humans, chimpanzees) but not extensively in others (gorillas). Or, which I think more likely, ape tool use draws upon other cognitive adaptations that are related to social learning and interactions, and actually using tools is a sometimes-beneficial side effect.

In a related story this week, a group of experimenters found that chimpanzee social learning involves imitation of the techniques observed from other individuals, instead of merely copying the goals of those individuals. Chimps are conformists, in other words.

From my weblog:

Using this procedure, the experimenters introduced a device that would vend food to the chimpanzees. The device could be worked in either of two ways: by using a stick to lift a hook, or by using the same stick to poke a flap. The workings of the device inside are not visible from the outside, although both lifting and poking are always available to the chimpanzee using the device.

The question is, when chimpanzees learn extractive foraging techniques, how much of the learning is direct imitation of the techniques they see others doing, and how much is emulative learning by individual experimentation?

The results showed that even when the chimpanzees experimented with the apparatus themselves and learned both ways to get the food, they still tended to adopt the method that predominated in their group. I would guess that this trend toward learning the techniques in the group is important for learning social roles and interactions with other individuals.

Personally, I know many people in my field of science who are doing other things because of the lack of academic jobs. Big pharmaceuticals and other corporations can use people with graduate degrees in almost any kind of science, because they have the statistical and/or logical toolkits that can be applied to other work. So these folks would be counted as doing work "outside their field of training", and are doing so because of "greater financial opportunities".

If anything, though, this doesn't mean there is a shortage of jobs for science and engineering degrees. It means that there are a shortage of people qualified to do trained statistics and problem-solving, and corporations are willing to pay a premium to raid surplus academics to get them.

One of my friends thinks a good candidate for selection would be avoidance of cities, since these were cholera-ridden population sinks for most of history. Maybe so.

Really the reason to think that cognition is involved is that these same genes were selected repeatedly in primate and human evolution:

Both genes underwent repeated adaptive subtitutions in the primate lineages leading to humans: these changes in Microcephalin were concentrated in the ancient hominoid ancestors of humans and chimpanzees; ASPM fixed a new adaptive substitution on average every 300,000 or so years since the human-chimpanzee common ancestor. Disease-causing alleles of both genes are associated with forms of microcephaly. The normal functions of neither have been characterized, although their effects in microcephaly would indicate that one important function is in early neural growth and differentiation. Thus, it is reasonable to think that they may have been involved in the evolution of brain size and structure in humans and other primates.

I suppose it's possible they make you dumber. But then further experiments should show one way or the other.

Sure, some of the things that used to kill a lot of people don't so much anymore. People even survive and have kids with CF today.

But selection requires only an incremental increase in reproduction. In a big population like ours, this increase can be as small as tenths or hundredths of a percent. This is so small that practically we will never measure it. Yet in a few thousand generations, this tiny reproductive effect will completely transform a population -- even a population of billions.

That's the problem with predicting the future -- what will be important then, we can't observe happening today. But there is plenty of reason to think that things are happening now. From my weblog:

Today, with 6 billion humans, every one-off mutation from the human consensus genome sequence occurs in dozens of people. Many multiple-off mutations occur in some people. In a larger population, selection is more potent, because genetic drift is weaker. This means that the advantageous variants of the next fifty millennia are already appearing in the world today, and may inevitably be selected. The global population is exploring the entire mutational space, many times over, and novel mutations are no longer likely to disappear so rapidly due to genetic drift. Any near variants that confer an advantage are already on the way to fixation. Many of these may lose their advantage once biomedical technology catches up to them. But others will be more subtle, more difficult to market in pharmaceutical form, and these will slowly, steadily increase.

Well, it sure might look that way, but these genes strongly suggest that something related to cognition was under strong selection throughout history.

One of the two genes, ASPM, appears to have come under selection only 5800 years ago; but it is now at around 20 percent, with a frequency of near 50 percent in some Near Eastern populations. Whatever this allele does, it had a selective advantage of more than 5 percent. They don't know it necessarily makes people smarter, but it's hard to think what else it might be.

That's really the neat part; that it shows that this idea of "survival of the dumbest" is apparently not what has been happening. Instead, there is every reason to think we have been getting smarter.

The submission doesn't mention the most problematic part: These alleles are high frequency in some populations, but absent or low frequency in others -- suggesting there may be adaptive differences in the brain among human populations. From my weblog post:

Geneticists are increasingly finding genetic variants that affect behavior. Several of these variants are now known to vary in frequency in different human populations. These alleles are two; the 7r allele of the dopamine receptor D4 (DRD4) gene is another that influences ADD/ADHD susceptibility (Harpending and Cochran 2002). The selective structure underlying DRD4 variation may be frequency-dependent, with different alleles correlating with alternative behavioral strategies that pose greater or lesser advantages in some populations. It is not clear whether such a mechanism is true of ASPM and Microcephalin; the selected alleles have risen to such high frequencies in some populations that it seems they are not mere alternatives; they are unilaterally advantageous -- at least where they have become common already.

It's a common misconception that Neandertal mtDNA has proved that they went extinct. That is one interpretation of the data. Here's another:

The real elephant under the rug of these papers (or as I've said elsewhere, the 800-pound gorilla) is natural selection. Both of the papers rely on the assumption that mtDNA is neutral. This is, in a sense, necessary to the papers' existence, since without this assumption mtDNA may be considered to be completely uninformative about the Neandertal problem. But there are good reasons to think that mtDNA has been under positive selection recently in human prehistory. Most notable among these reasons is the fact that human mtDNA violates every test of neutrality. Also suggestive is the limited mtDNA variation among the known Neandertal sequences--a suggestion that the positive selection that has affected human mtDNA recently may be just the most recent of several episodes throughout human evolution. Until papers like these take the issue of selection seriously, there is little chance of finding consensus on the Neandertal genetic problem.

If they were under selection, Neandertal mtDNA would be gone, but some other genes might well remain. It's another hypothesis, but it may be demonstrated sooner than you think, since people are trying to reconstruct the Neandertal genome!

It's a common misconception that Neandertal mtDNA has proved that they went extinct. That is one interpretation of the data. Here's another:

The real elephant under the rug of these papers (or as I've said elsewhere, the 800-pound gorilla) is natural selection. Both of the papers rely on the assumption that mtDNA is neutral. This is, in a sense, necessary to the papers' existence, since without this assumption mtDNA may be considered to be completely uninformative about the Neandertal problem. But there are good reasons to think that mtDNA has been under positive selection recently in human prehistory. Most notable among these reasons is the fact that human mtDNA violates every test of neutrality. Also suggestive is the limited mtDNA variation among the known Neandertal sequences--a suggestion that the positive selection that has affected human mtDNA recently may be just the most recent of several episodes throughout human evolution. Until papers like these take the issue of selection seriously, there is little chance of finding consensus on the Neandertal genetic problem.

If they were under selection, Neandertal mtDNA would be gone, but some other genes might well remain. It's another hypothesis, but it may be demonstrated sooner than you think, since people are trying to reconstruct the Neandertal genome!

There are two central issues. One is that the "Aurignacian" industry, which is proposed to have been made by modern humans, may not actually have been a single industry across Europe. In the current study, the "interleaving" of the two kinds of tools is documented by around 10 artifacts, out of 750 total.

The other issue is that no fossil remains of modern humans have yet been found associated with early "Aurignacian" tools. We simply don't know who made them. Since they are not technically very different from the Neandertal-associated Chatelperronian, it is hard to say that there is a real cognitive difference represented by those tools, whoever made them.

I have some pictures of the tools on my weblog post (John Hawks Anthropology Weblog), and conclude this:

But when two pictures look like the ones above, and they are supposed to be typologically identifiable products of "modern humans" on the one hand, and "Neandertals" on the other -- well, it seems to me there needs to be a bit more than an edge of retouch behind that conclusion.

--John

There are two central issues. One is that the "Aurignacian" industry, which is proposed to have been made by modern humans, may not actually have been a single industry across Europe. In the current study, the "interleaving" of the two kinds of tools is documented by around 10 artifacts, out of 750 total.

The other issue is that no fossil remains of modern humans have yet been found associated with early "Aurignacian" tools. We simply don't know who made them. Since they are not technically very different from the Neandertal-associated Chatelperronian, it is hard to say that there is a real cognitive difference represented by those tools, whoever made them.

I have some pictures of the tools on my weblog post (John Hawks Anthropology Weblog), and conclude this:

But when two pictures look like the ones above, and they are supposed to be typologically identifiable products of "modern humans" on the one hand, and "Neandertals" on the other -- well, it seems to me there needs to be a bit more than an edge of retouch behind that conclusion.

--John

Ancient DNA is generally fragmented into pieces only a few hundred nucleotides long (in comparison to a total genome length of 3 billion). To reconstruct longer sequences, a complete series of damaged fragments is needed, with enough overlap to connect them together. So in my opinion, even fairly short segments of around 100kb are far more effort than anyone is likely to put into it.

On the other hand, this reconstruction of the genome from short fragments is exactly the "shotgun" approach that Craig Venter successfully used in the Human Genome Project. With enough computerization, who knows?

I have a post on this topic on my anthro weblog.

To make a long story short, with this group of researchers, the odds are that there already have been some results that haven't yet been reported.

My own guess is that they have cloned the FoxP2 language gene -- a gene that the same lab is responsible for most of the work on. The arguments presented by this group have consistently been critical of the likelihood of contamination if the results are like a modern human gene. This leads me to believe that their results probably show this gene to be non-humanlike, which wouldn't be a surprise, since the gene itself has undergone a recent selected change in humans.

Anyway, check out the link for more info.

I have a post on this topic on my anthro weblog.

To make a long story short, with this group of researchers, the odds are that there already have been some results that haven't yet been reported.

My own guess is that they have cloned the FoxP2 language gene -- a gene that the same lab is responsible for most of the work on. The arguments presented by this group have consistently been critical of the likelihood of contamination if the results are like a modern human gene. This leads me to believe that their results probably show this gene to be non-humanlike, which wouldn't be a surprise, since the gene itself has undergone a recent selected change in humans.

Anyway, check out the link for more info.

1. Google is many times faster. I spend very little time waiting for what I want.
2. Google often links to full text or PDF versions of articles directly, again saving much time and many steps in finding content.
3. Google indexes citations within all web-accessible content, including chapters from edited volumes and many foreign journals that have been posted by their authors. This stuff is not typically available on WoS.
4. Did I mention that Google is many times faster? I rarely have finished a WoS search in less than three minutes; Google generally has my results in seconds.
5. Google often links directly into PubMed and other database services, allowing me to access their tools with a single click.
6. The fewer citations reported by Google in a citation search make it much faster to find what I need when what I need is one of the most common citations. Google also appears to be much better about not duplicating entries.
7. Hello, searching by author's first name? A novel concept, I know...