When it comes to skin color, the idea that we're really all the same isn't just a utopian dream. A look at skin cancer from an evolutionary perspective suggests that maybe once we were all white; then we were all black; then some of us went back to white.

A scientist argues that once we were all white; then we were all black; then some of us went back to white.

In a study published in Proceedings of the Royal Society B, Mel Greaves, professor of cell biology at the Institute of Cancer Research in London, looked at some 25 studies of skin cancer in albinos in Africa. Albinos have less melanin, a natural pigment that helps protect the skin against damage from the sun. The more melanin in the body, the darker the skin.

Greaves found that basal cell and squamous cell carcinomas are not relatively harmless diseases of old age. In African albinos, they kill early and quickly. Skin cancer prevention, he concludes, was a driving force in human evolution to dark skin. Other scientists, including Charles Darwin, have long dismissed skin cancer as a force in evolution because it typically strikes those past childbearing age.

Greaves, who studies the role that disease plays in human evolution, believes his study adds credence to the idea that when earlier hominids shed their shaggy hair about two million years ago, exposing their naked, pale skin to the sun on the sun-drenched savanna of Africa, natural selection favored those who had the darkest variations in skin color to protect against the ultraviolet radiation (UVR) that can cause skin cancer.

Much later, about 50,000 to 100,000 years ago, those who migrated to cold northern climates no longer needed that protection, and evolved back to pale skin. National Geographic talked with Greaves about his research.

You point to skin cancer as a reason that skin color evolved. Among cancers, is skin cancer unique in influencing evolutionary protections?

I can't think of any other cancer and circumstance that would have had a sufficiently large impact on survival and reproduction. You might think that pediatric cancers might have been subject to evolutionary selection, but my guess is that they have always been too rare to provoke protective selection.

Can you explain when and why our human ancestors became black?

The genetic evidence suggests that black skin became the norm in Africa some 1.2 million years ago, around the time that early humans were colonizing the savanna and had lost most of their body hair. Most investigators believe that black pigmentation was an essential adaption to protect naked, pale skin against solar ultraviolet radiation, which is high all year round near the equator.

There has been consensus on some of the life-threatening impacts of UVR via the skin. Ideas have included damage to sweat glands and degradation of folate and other essential nutrients in blood circulating through the skin.

But skin cancer has been universally rejected as a possible selective force for the adaptation of black skin. This is on the grounds that in modern-day Caucasians, it is usually benign or is lethal too late in life to influence evolution. In my paper I suggest this is taking cancer out of the relevant context and that the experience of African albinos illustrates very vividly what the impact of intense UVR might have been on early humans.

Why did some people then evolve back to the white skin that was originally underneath hominids' hair?

As our human ancestors migrated out of Africa, those that moved away from equatorial and tropical regions underwent positive selection for paler skin. This was in part due to the reduced pressure from UVR skin damage, but also because black skin became a disadvantage, possibly because [pale skin is better at generating vitamin D] and dark skin is more susceptible to frostbite.

So you're saying that skin cancer played a part in skin color: Humans were originally white under all their hair, then evolved to black a million or two million years ago, then 50,000 to 100,000 years ago some went back to white as they migrated farther north?

That's exactly what I am suggesting. But unless Jared Diamond and Darwin [two scientists who dismissed skin cancer as a factor in evolution] are right and skin color variation is just incidental and endorsed by sexual preferences, then there has to be an evolutionary logic.

Naturally there is considerable speculation in all of this debate, and coming up with a definitive, unambiguous explanation for events that happened millions of years ago is very difficult, if not impossible. We are trying to come up with the most plausible answer in the light of all the evidence available—which is the way science always works.

Credit: National Geographic

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"Women talk as a little girl plays with a toy gun during a religious celebration. In traditional families men and women gather separately."

Iran remains largely misunderstood by many of us in the West. As a theocratic country kept under rigid social, religious, and media restrictions, it’s difficult to relate to. And in the absence of much tourism or Western media based in Iran, for many Americans the country is a blank canvas for their own assumptions and conjectures.

Iranian Living Rooms by photographer Enrico Bossan tries to close that distance. It’s a book of photographs taken in the domestic havens where Iranians, very much like the wider Western world, indulge in drink, smoking, sex and radical ideas. It’s where they express the casual lifestyles that thrive despite the preferences of Iran’s government.

To get a glimpse behind the official party lines, Bossan decided against taking the photos himself. Instead, he asked 15 young photographers already living in the country to document the Iran they know better than anyone.

“Not many [outsiders] know,” says Bossan, “because unless you are going to be traveling inside the country — say you have a friend and you have the possibility to go to a dinner with some Iranians in a private house — you will see another kind of country. I don’t like to invite someone to shoot a world they don’t know. I believe that it’s better that somebody shoot or tell a story about what they know.”

In March of 2013, as the country’s election approached, Bossan and a colleague created a private page online where young Iranian photographers could submit their portfolios. They got more than 60 applications, and after visiting the country to hold meetings and clandestine workshops the list was finally shortened to 15. Each photographer had their own ideas and proposals for the project — Bossan’s job was to curate their ideas and coach the photographers remotely as they gathered the images that eventually made up the book. One requirement was that they had to document the lives of people they knew, to share their personal view of authentic daily life.

“We didn’t want any portrait or a fake portrait, but asked them to show us their most realistic daily life,” Bossan says. “Being so realistic was a problem for some of them, because it portrays exactly what is private. To smoke, to drink, to go dancing, to make love without being married.”

Bossan became fascinated by the competing spheres of Iranian identity while visiting the country in 1989. It was ten years after Ayatollah Khomeini’s Islamic revolution and overthrowing of the Shah, and Iran had adopted strict social, religious and political regulations that included limits on public speech, imposing dress codes for women, and enforcing prohibitions on alcohol.

Despite the recent election of Hassan Rouhani — a more liberal-seeming president than Ahmadinejad was — things haven’t loosened up much. Smoking has since been outlawed, and access to the Internetremains restricted. Even dancing can be risky, but in a country where 65% of the population are under 30, subversion is inevitable.

During his visit, Bossan could sense a tension between the strict public face of post-revolutionary Iran with another way of life carrying on behind the drawn blinds of Iranian homes and private spaces. What he never saw were the photographs that illuminated this hidden aspect of its culture. “I saw more pictures, more stories related to people in the streets, revolution, religion, chador,” he says, “but no interesting work of them inside their houses, and specifically inside their living rooms.” Those are the photos he tried to get with Iranian Living Rooms.

Throughout the book’s 15 stories, we are shown the day-to-day lives of Iranian people young and old, leading lives not at all different from those led by folks throughout the States. We also see the secret costume parties, nail salons, makeup styles, and questionable habits like smoking and drinking that are common to most cultures — the difference here is that many of these activities could carry stiff penalties for the subjects of the photos. Iranian Living Rooms aims to engage Western readers with a slice of Iranian life they wouldn’t otherwise see, and in doing so demonstrate how undifferentiated the two cultures really are.

The book also allowed a young generation of Iranian photographers their first chance for international exposure. As the editorial head of Fabrica, a communications thinktank owned by global fashion giant Benetton, Bossan could offer the photographers resources for refining and publishing their work. However, the photographers also risked punishment if the project ran afoul of the government,

“To protect them, we decided not to show every picture online — we talked with them, and we talked with my friend, the curator and the writers, we proposed to have a list of pictures on an embargo to save them from any kind of attack from inside based on religion or politics.“

Even after the launch, some problems came up. Due to U.S. embargoes, the book was automatically denied payment service through Paypal, but the misunderstanding was resolved quickly. The book — its ornate cover a nod to the distinctive Iranian carpets — remains for sale online only.

Bossan plans to revisit the formula that made Iranian Living Rooms a success. To him, it represents a more honest look at its subject, less prone to the prejudices of a photographer who’s influenced by the imposed isolation between the regular folk of our respective cultures.

“We can see this in many other countries of the world,” Bossan says. “The [common] attitude about how to represent Iran is completely false in terms of the reality.”

Credit: Tajik Ali

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