MedWorm Tags: human evolution

We Each Have About 60 Unique Genetic Mutations

FuturePundit — Mon, 13 Jun 2011 23:00:00 +0100

You are a mutant. Don't deny it. Accept your role in the mutant horde. Each one of us receives approximately 60 new mutations in our genome from our parents. This striking value is reported in the first-ever direct measure of new mutations coming from mother and father in whole human genomes published today. For the first time, researchers have been able to answer the questions: how many new mutations does a child have and did most of them come from mum or dad? The researchers measured directly the numbers of mutations in two families, using whole genome sequences from the 1000 Genomes Project. The results also reveal that human genomes, like all genomes, are changed by the forces of mutation:... (Source: FuturePundit)

Evolution and Liberty

Cato-at-liberty — Tue, 13 Jul 2010 16:10:48 +0100

By Jason KuznickiPolitical scientist Larry Arnhart heads this month’s Cato Unbound. He argues that libertarians need to integrate biological evolution into their thinking about human cultures and even politics. More provocatively, he claims that the “a Darwinian science of human evolution supports classical liberalism.” This is the case, he argues, even though market competition differ[s] radically from biological competition. Biological competition is a zero-sum game where the survival of one organism is at the expense of others competing for the same scarce resources. But market competition is a positive-sum game where all the participants can gain from voluntary exchanges with one another. In a liberal society of free markets based on voluntary exchanges, success dep...

Admixture between humans and the Others

Gene Expression — Wed, 21 Apr 2010 04:32:06 +0100

Mr. Carl Zimmer points me to a new article in Nature, Neanderthals may have interbred with humans. The details within the article are more tantalizing, it seems to me, than the headline would imply. The topline is this, researchers presented the following at the recent meeting of the American Association of Physical Anthropologists: * An analysis of 614 highly variant loci, microsatellites, in ~2,000 people from diverse populations imply some variants which seem to be derived from human lineages outside of the mainline which led to the anatomically modern humans who left Africa 50-100,000 years before the present to settle the world. I assume there were “long branches” on the phylogenies of some loci, indicating that some of the alleles were “separated” from others ...

Increased rate of encephalization

Gene Expression — Mon, 05 Apr 2010 06:16:28 +0100

A week ago I pointed to a controversy about the rate of growth of human cranial capacities over the past few million years. I asserted that the rate of growth was gradual, with no major discontinuity. Over at Genetic Inference Luke Jostins’ has done a more formal analysis. He finds: The model shows a definite speed-up of brain size increase recently, and fits the data significantly better than a simple trend line (F(1,90) = 15.8, p < 10^-5). I estimate that the speed-up occured 252kya, and can say with 95% confidence that it lies between 203 and 377 kya. This result is pretty robust to exactly what model we use; I also tried using a model where brain size grew exponentially with time, and this gave a similar break-point: 250kya, with a 95% interval of 167-402 kya (see this graph). Re...

Thomas Malthus was right. Mostly

Gene Expression — Mon, 29 Mar 2010 23:38:08 +0100

John Hawks has an excellent post rebutting some misinformation and confusion on the part of Colin Blakemore, an Oxford neurobiologist. Blakemore asserts that: * There was a sharp spike in cranial capacity ~200,000 years ago, on the order of 30% * And, that the large brain was not deleterious despite its large caloric footprint (25% of our calories service the brain) because the “environment of early humans was so clement and rich in resources” Hawks refutes the first by simply reposting the chart the above (x axis = years before present, y axis = cranial capacity). It’s rather straightforward, I don’t know the paleoanthropology with any great depth, but the gradual rise in hominin cranial capacity has always been a “mystery” waiting to be solved (see Gro...

The Mysterious Other

Gene Expression — Sun, 28 Mar 2010 07:41:48 +0100

Last week Nature published a paper which may have found a new ‘branch’ of the hominin evolutionary bush which may have been coexistent which modern humans and Neandertals. I recommend The Atavism, Carl and John Hawks on this story. Interesting times. (Source: Gene Expression)

Y Chromosome Still Evolving

FuturePundit — Wed, 13 Jan 2010 00:00:00 +0100

Some have theorized that the Y chromosome is in decline, that the chromosome that makes men into men is losing out in the rush of evolution. But no. I'm sure many guys will be happy to know that the Y chromosome is evolving under heavy evolutionary pressure. CAMBRIDGE, Mass. (January 13, 2010) Contrary to a widely held scientific theory that the mammalian Y chromosome is slowly decaying or stagnating, new evidence suggests that in fact the Y is actually evolving quite rapidly through continuous, wholesale renovation. By conducting the first comprehensive interspecies comparison of Y chromosomes, Whitehead Institute researchers have found considerable differences in the genetic sequences of the human and chimpanzee Ysan indication that these chromosomes have evolved... (Source: FutureP...

Shellfish & the human bottleneck

Gene Expression — Thu, 17 Dec 2009 02:02:00 +0100

How shellfish saved the human race:Turns out, somewhere between 130,000 to 190,000 years ago, the human species was reduced to less than 1000 breeding individuals--just a few thousand people in total. Ancient, naturally driven climate change pushed our species to the brink, said Curtis Marean, Ph.D., a professor with the Institute of Human Origins and the School of Human Evolution and Social Change at Arizona State University.What saved us? According to Marean, the answer may be "shellfish"."They're a great source of protein," he said. "And shellfish are immune to colder ocean temperatures. In fact, when the water gets colder, those populations go up."Marean used climate models to pinpoint locations in Africa where human hunter-gatherers could have hunkered down during a long glacial perio...

FOXP2 in Nature

Gene Expression — Wed, 11 Nov 2009 22:08:00 +0100

Human-specific transcriptional regulation of CNS development genes by FOXP2:...It has been proposed that the amino acid composition in the human variant of FOXP2 has undergone accelerated evolution, and this two-amino-acid change occurred around the time of language emergence in humans...However, this remains controversial, and whether the acquisition of these amino acids in human FOXP2 has any functional consequence in human neurons remains untested. Here we demonstrate that these two human-specific amino acids alter FOXP2 function by conferring differential transcriptional regulation in vitro. We extend these observations in vivo to human and chimpanzee brain, and use network analysis to identify novel relationships among the differentially expressed genes. These data provide experimenta...

Humans Evolving Toward Earlier Childbirth?

FuturePundit — Mon, 19 Oct 2009 23:00:00 +0100

Here's a study that finds that humans are still under selective pressure. Durham, NC Although advances in medical care have improved standards of living over time, humans aren't entirely sheltered from the forces of natural selection, a new study shows. "There is this idea that because medicine has been so good at reducing mortality rates, that means that natural selection is no longer operating in humans," said Stephen Stearns of Yale University. A recent analysis by Stearns and colleagues turns this idea on its head. As part of a working group sponsored by the National Evolutionary Synthesis Center in Durham, NC, the team of researchers decided to find out if natural selection a major driving force of evolution... (Source: FuturePundit)

100 To 200 New Mutations Per Person

FuturePundit — Fri, 04 Sep 2009 23:00:00 +0100

We've each got our own unique genetic mutations. Each person has 100-200 new genetic mutations that their parents did not have. Scientists at the Wellcome Trust Sanger Institute and colleagues... (Source: FuturePundit)

Genes Found Unique To Humans

FuturePundit — Mon, 31 Aug 2009 23:00:00 +0100

3 genes have been identified that appear unique to humans and we might have a total of 18 genes unique to us. In this work, David Knowles and Aoife McLysaght... (Source: FuturePundit)

Sex Ratio At Birth Rises In Vietnam

FuturePundit — Mon, 02 Mar 2009 05:00:00 +0100

Selective abortion of female fetuses is common in China, India, and some other Asian countries. A Plos One report finds that Vietnam shows signs of following the same pattern with... (Source: FuturePundit)

Transbeman, the era of CyberConsciousness (or the Death of Death?)

Women's Bioethics Blog — Sat, 21 Feb 2009 20:46:18 +0100

This past week, I had the pleasure of attending a private screening of Transbeman, a techno-fable film produced by Martine Rothblatt, that explores ethical, legal, and social implications of techno-immortality. I've asked for a clip/teaser to post, so that our readers can get a flavor for the film, but I can tell you that it is thoughtful, provocative, and raises many questions that would be a lot of fun to discuss in law classes or bioethics classes.In an interview with We magazine, we get a peek into Martine's motivation: trying to make the world a better place. The problem, she explains is not that we are not smart enough, but that we are not empathetic, or kind, or compassionate enough, and the film explores that issue, masterfully. (And in the interest of full disclosure, Martine and ...

Thoughts on the Evolution of Women's Emotionality

Gene Expression — Fri, 23 Jan 2009 15:57:00 +0100

Women are more emotional than men. They experience more negative and more positive emotions. They're better at empathizing than men. They're better at recognizing the emotions on peoples' faces. All of these traits are significantly heritable, pointing to a partially genetic (and therefore evolutionary) basis.So, from an evolutionary standpoint, why are women more emotional? The conventional story that I've heard is that higher emotionality confers a fitness benefit by strengthening the bond between the mother and her children. Additionally, I've heard that women evolved higher empathy because their gender's social structure (less hierarchical, more social) required it.Emotionality in mate selection is typically presented as a side-effect of these evolutionary causes. Lately, I've come to ...

Can Human Cultural Influences be Causing the "Disappearing Male?"

Secondhand Smoke — Mon, 10 Nov 2008 00:25:00 +0100

Put this post in the Total Conjecture File. A story about the decline in male fertility and increasing birth defects among male babies got me to wondering: Is it possible that human biological evolution can be impacted by the changes in perception caused by radically evolving cultural trends? From the story:Are males becoming an endangered species? That's the question scientists and researchers have been pondering since alarming trends in male fertility rates, birth defects and disorders began emerging around the world.More and more boys are being born with genital defects and are suffering from learning disabilities, autism and Tourette's syndrome, among other disorders. Male infertility rates are on the rise and the quality of an average man's sperm is declining, according to some studie...

Disease driven human evolution?

Gene Expression — Thu, 30 Oct 2008 04:04:00 +0100

Gene Expression Profiles during In Vivo Human Rhinovirus Infection (also, ScienceDaily summary):Rhinovirus infection significantly alters the expression of many genes associated with the immune response, including chemokines and antivirals. The data obtained provide insights into the host response to rhinovirus infection and identify potential novel targets for further evaluation..About those viruses:Epidemiologists have established minimal population size and density thresholds for particular diseases (such as measels, mumps, rubella, smallpox, influenza, rhinovirus) to survive and spread. In small hunter-gatherer groups or even small farming villages, such diseases would have been incapable of spreading very far and woul have disappeared (Black 1975). This implies that many diseases must...

Human Evolution Over?

Secondhand Smoke — Tue, 07 Oct 2008 01:22:00 +0100

This is the kind of "science" story that drives me crazy. A scientist hypothesizes that "human evolution is over"--and it is taken seriously. From the story:Human evolution is grinding to a halt because of a shortage of older fathers in the West, according to a leading genetics expert. Fathers over the age of 35 are more likely to pass on mutations, according to Professor Steve Jones, of University College London.Speaking today at a UCL lecture entitled "Human evolution is over" Professor Jones will argue that there were three components to evolution--natural selection, mutation and random change. "Quite unexpectedly, we have dropped the human mutation rate because of a change in reproductive patterns," Professor Jones told The Times. "Human social change often changes our genetic future,"...

Selection speculation: CLOCK and reward-dependence in Africans

Gene Expression — Mon, 02 Jun 2008 09:39:00 +0100

Since so many comments lead off with some variant of "I would guess," why not try to corrall them all into one post where they could serve a purpose? Each week I'll find some area of the human genome that shows signs of recent selection, see what phenotypes the gene affects, and although I'll likely provide the most convincing story, readers can conjecture to their heart's content about what might have driven selection. It may, for once, improve the discussion to comment while still deranged from last night's drink.Let's start with the data: using Haplotter, we see that for the gene CLOCK, there is a signal of recent selection in Africans but not in Europeans or Asians. The CLOCK gene is involved in maintaining our circadian rhythm, and I started this search looking for between-group diffe...

Male preferences and debunking myths about the evolution of the female form

Gene Expression — Mon, 19 May 2008 01:49:00 +0100

Click for UncensoredIn the comments section to a 2blowhards post on booty shakin', blogger Alias Clio puts forth an argument from incredulity regarding several hypotheses I proposed: 1) that male preferences for different parts of the female body have, over time, correlated with personality traits; 2) that natural selection has had a role in causing some men to prefer one body part over another; and 3) that the correlation could be caused by some simple mechanism. She also repeats an evolutionary just-so story about why human females developed large breasts -- that is has something to do with face-to-face sex -- and that too is worth taking a hard look at (the story, that is).As to 1), the available data do paint a somewhat clear picture that assmen, boobmen, and legmen are not the same on...

Cochran And Harpending See Human Evolution Acceleration

FuturePundit — Tue, 11 Dec 2007 05:00:00 +0100

Evolutionary theorist Greg Cochran and genetic anthropologist Henry Harpending have teamed up again and with John Hawks, Eric Wang, and Robert Moyzis to argue that human evolution has greatly accelerated... (Source: FuturePundit)

Some Neanderthals Were Redheads

FuturePundit — Thu, 25 Oct 2007 04:00:00 +0100

Geico should run a cave man commercial with a red head cave man. Or one of the caveman TV show actors should have red hair. CAMBRIDGE, Mass. -- Ancient DNA... (Source: FuturePundit)

Cochran And Hawks Detect Human Evolution Acceleration

FuturePundit — Thu, 29 Mar 2007 04:00:00 +0100

Evolutionary theorist Gregory Cochran and anthropologist John Hawks claim to have found evidence of a huge increase in the rate of human evolution in the more recent period of human... (Source: FuturePundit)