oldowan: Blond hair evolved independently in Pacific islands Science can’t yet tell us whether they have more fun – but it has uncovered a new genetic change that makes people blond. And contrary to long held belief, it seems golden hair hasn’t simply been introduced across the globe by travelling tow heads, but instead evolved separately in different human populations. Indigenous people of the Solomon Islands in the South Pacific have some of the darkest skin pigmentation outside of Africa. But unlike most other tropical populations, they also have a high prevalence of blond hair. Up to 10 per cent of the population is fair haired, the highest proportion outside of Europe. Until now, this odd trait had generally been attributed to the introduction of blond genes by European explorers and traders in preceding centuries. “We originally thought, well that must be a Captain Cook allele,” says Carlos Bustamante at Stanford University. Yet a closer look revealed that the genetics behind blond hair in Brussels are distinct from those leading to flaxen locks in the South Pacific.

oldowan:

Blond hair evolved independently in Pacific islands

Science can’t yet tell us whether they have more fun – but it has uncovered a new genetic change that makes people blond. And contrary to long held belief, it seems golden hair hasn’t simply been introduced across the globe by travelling tow heads, but instead evolved separately in different human populations.

Indigenous people of the Solomon Islands in the South Pacific have some of the darkest skin pigmentation outside of Africa. But unlike most other tropical populations, they also have a high prevalence of blond hair. Up to 10 per cent of the population is fair haired, the highest proportion outside of Europe. Until now, this odd trait had generally been attributed to the introduction of blond genes by European explorers and traders in preceding centuries. “We originally thought, well that must be a Captain Cook allele,” says Carlos Bustamante at Stanford University.

Yet a closer look revealed that the genetics behind blond hair in Brussels are distinct from those leading to flaxen locks in the South Pacific.

3 weeks ago

Mitochondrial DNA haplotypes of Devensian hyaenas from Creswell Crags, England

I love it when clever proxies are used to answer questions of human dispersal events. This recent paper by Danae Doge and colleagues used aDNA from hyenas to give us a greater understanding of when the repeated colonization of the UK. I know I will be citing it soon. 

3 weeks ago

The Evolution of Skin

oldowan:

Skin is the body’s largest organ, and one with a complex cultural and evolutionary past. At the upcoming SciCafe on Wednesday, May 2, biological anthropologist Nina Jablonski will discuss how human skin evolved, particularly as an adaptation to ultraviolet radiation. She recently answered a few questions about skin and its role in our lives.

When did you decide to study the history of human skin?

Nina Jablonski: By accident. About 23 years ago, a colleague asked me to give a lecture to his class about skin because he was going to be out of town for a conference. I obliged. In preparing for the lecture, I realized just how little had been written about the evolution and meaning of human skin.

Why is human skin unique?

Jablonski: The “primary uniqueness” of human skin is that it is mostly hairless. Because of this, the skin itself, rather than hair covering it, is the body’s main protection against physical assault. Many of the most important and distinctive attributes of skin are consequences of hairlessness. Our mostly hairless skin is tough, colorful, and available for deliberate decoration.

How do climate and geographical location affect skin color?

Jablonski: Skin color is closely related to intensity of ultraviolet radiation, or UVR. Higher concentrations of melanin pigment are protective against high levels of UVR. Lower levels of melanin are an adaptation to lower UVR. Modern humans evolved in equatorial Africa over 120,000 years ago, and our original skin color was dark. As humans dispersed outside of equatorial latitudes beginning around 80,000 years ago, populations entering the highest latitudes with the lowest UVR underwent genetic changes leading to loss of pigmentation.

Is human skin still evolving?

Jablonski: It may still be evolving, but not at the same rate it did earlier in our history. Modern humans use mostly cultural means like clothing and shelters to protect themselves from extremes of sunlight and temperature. Our skin is no longer under the environmental stress that it was, say, 50,000 years ago.

What effect are modern indoor lifestyles having on our skin?

Jablonski: The biggest effect that modern lifestyles have on us is the slowing or prevention of vitamin D production in the skin. Most people today live in cities and are protected from the UVR that starts the process of vitamin D production in skin. As a result, many people are deficient in this important vitamin.

What’s the most misunderstood thing about human skin?

Jablonski: People generally don’t appreciate just how much their skin does for them, in being a protective covering, a biochemical factory, and a canvas for self-expression.

3 weeks ago
”

Nobody fears the height, you all just fear the fall. Go to the edge sometime, and prove your body wrong. You land badly, but you crash standing.

Dessa
2 months ago

Reblog if you want your followers to tell you one thing they secretly think about you.

(Source: blindspotsandsunshine, via fatallysincere)

2 months ago
Let’s all keep in mind that PLOS publishes open source because authors pay them to check their methods, but not their interpretations. Just a skeptics view on this fantastic find (Come on the right side is signifcantly emphasized in the matrix!) alphacaeli: commonunity: human fossils hint at new species. The bones, which represent at least five individuals, have been dated to between 11,500 and 14,500 years ago. But scientists are calling them simply the Red Deer Cave people, after one of the sites where they were unearthed. The team has told the PLoS One journal that far more detailed analysis of the fossils is required before they can be ascribed to a new human lineage. “We’re trying to be very careful at this stage about definitely classifying them,” said study co-leader Darren Curnoe from the University of New South Wales, Australia. “One of the reasons for that is that in the science of human evolution or palaeoanthropology, we presently don’t have a generally agreed, biological definition for our own species (Homo sapiens), believe it or not. And so this is a highly contentious area,” he told BBC News. follow the link to read on Hmm… Their “most complete” skull looks a bit deformed to me. A lot of what they described in the PLoS article doesn’t seem too wildly out of the range of modern human variation. There’s also the age range to consider: given the rate at which speciation occurs, between 14,500 and 11,500 years ago isn’t really long enough to develop into a new species, let alone warrant a new species label. My (admittedly tentative) bet is that the relative isolation of the Red Deer Cave population has just meant a population of robust archaic H. sapiens have persisted with little gene flow in or out to alter or diversify their features. The DNA will be interesting when they get it. I like that they’re being circumspect with regards to taxanomic attribution though I’m not so convinced that these fossil represent a new lineage. Then again, talking this stuff up is what gets you grants.

Let’s all keep in mind that PLOS publishes open source because authors pay them to check their methods, but not their interpretations. Just a skeptics view on this fantastic find (Come on the right side is signifcantly emphasized in the matrix!)

alphacaeli:

commonunity:

human fossils hint at new species.

The bones, which represent at least five individuals, have been dated to between 11,500 and 14,500 years ago.

But scientists are calling them simply the Red Deer Cave people, after one of the sites where they were unearthed.

The team has told the PLoS One journal that far more detailed analysis of the fossils is required before they can be ascribed to a new human lineage.

“We’re trying to be very careful at this stage about definitely classifying them,” said study co-leader Darren Curnoe from the University of New South Wales, Australia.

“One of the reasons for that is that in the science of human evolution or palaeoanthropology, we presently don’t have a generally agreed, biological definition for our own species (Homo sapiens), believe it or not. And so this is a highly contentious area,” he told BBC News.

follow the link to read on

Hmm… Their “most complete” skull looks a bit deformed to me.

A lot of what they described in the PLoS article doesn’t seem too wildly out of the range of modern human variation. There’s also the age range to consider: given the rate at which speciation occurs, between 14,500 and 11,500 years ago isn’t really long enough to develop into a new species, let alone warrant a new species label. My (admittedly tentative) bet is that the relative isolation of the Red Deer Cave population has just meant a population of robust archaic H. sapiens have persisted with little gene flow in or out to alter or diversify their features. The DNA will be interesting when they get it.

I like that they’re being circumspect with regards to taxanomic attribution though I’m not so convinced that these fossil represent a new lineage. Then again, talking this stuff up is what gets you grants.

(via rocks-n-bones-deactivated201203)

2 months ago

Sometimes writing an academic paper is like sculpting marble with your fists. 

2 months ago

The Most Astounding Fact (Neil DeGrasse Tyson)

2 months ago

Anonymous asked: This wasn't on the list. But what about: Dear Prof. Walpoff?

The second I posted that I thought of about 40 others that I could include. You are very correct about Wolpoff. Dr. Wolpoff

2 months ago

That awkward moment in reading a peer reviewed paper…

and realizing that a team of editors, PhD candidates, and professors didn’t notice the word melanocytes in a paper about the genetic basis for melanin was misspelled. Do I even cite this now? Melanocyte

3 months ago

Sometimes I want to find other intelligent life in the universe…

…so I can justify giving up on the one here. 

3 months ago

This seems healthy, actually.

democratsaresexier:

glmrklls:

I will write about the following, leave one in my ask box

Dear person I hate,

Dear person I like,

Dear ex girlfriend,

Dear ex bestfriend,

Dear bestfriend,

Dear *anyone*,

Dear Santa,

Dear mom,

Dear dad,

Dear future me,

Dear past me,

Dear person I’m jealous of,

Dear person I had a crush on

Dear girlfriend

Dear boyfriend 

Because I’m bored and you pity me?

(Source: waychil, via fatallysincere)

3 months ago

Who’s with me? I want to do this so bad. 

3 months ago

Reblog if you’ll answer anything that gets sent to you right now.

(via anarchistmom)

3 months ago

one penis too many

Deeply Catholic nation? The Italian archaeologist here goes to church every Sunday, participates in all the holidays, and probably holds the same moral outlook. He probably thinks we are all heathens here, which, of course, we are.. 

hornblende:

the lack of scholarly research on the “homosexual” wall inscriptions in Pompeii will always confuse and irritate me

it’s like, they can handle one penis. bc they talk about the phallic images and penis chimes. but then they see anything related to two penises and they’re just like NOT OUR DIVISION, THIS IS TOO MUCH PENIS FOR US.

how are Pompeian scholars so prudish?

(via rocks-n-bones-deactivated201203)

3 months ago