How Many Friends Does One Person Need? (14 page)

We have suspected for some time, for example, that modern birds are in fact the surviving descendants of one small family of dinosaurs. The discovery of a number of partially feathered dinosaurs in China during the 1990s added a new sense of excitement and only served to reinforce such a view. Then in 2008 came the news that molecular genetics had confirmed that this intuition was right. Birds do belong to the dinosaur family – or should that be the other way around?

This was real-life
Jurassic Park
stuff. Chris Organ from Harvard University and his colleagues carried out the first successful extraction of DNA from a sixty-five-million-year-old fossil
Tyrannosaurus rex
– the archetypal dinosaur if ever there was one. This is no small achievement, since extracting DNA samples from fossils is a tricky business. The older the fossil, the more likely it is that all the tissue has been transformed into inert stone. And even where some usable tissue has survived, the chances that the DNA can be extracted are at best poor because DNA degrades relatively quickly with time. The chromosomes break up and what you are left with is fragments of DNA that are often too short to be matched up against the DNA strands of another species.

Even then, undertaking a genetic analysis is not straightforward. You have to find the right bits of the chromosome to do these analyses. You need sections that do not code for functional parts of the body, because functional
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genes are subject to rapid and dramatic change under the influence of natural selection. Instead, you need chromosome segments that have no function and so change only as a result of random mutations, remaining in place because they neither benefit nor hinder the animal in its daily life. It is these that provide the basis of the ‘molec-ular clock’: by painstakingly determining how many of the base pairs in the DNA strand have mutated in each lineage since two species last had a common ancestor, we can determine how closely related they are and, more importantly, when they last shared that common ancestor.

So, armed with samples from a North American
T. rex
and a mastodon, Organ and his colleagues compared the DNA sequences for these two giants of the past with DNA from a range of living animals, including birds (represented by the humble domestic chicken and the ostrich), some primates (humans, chimpanzees and macaque monkeys), cows and dogs, rats and mice, modern elephants and a selection of reptiles, amphibians and fishes.

The genetic evidence places the mastodon just where we expect it to be (with the elephant), which gives us some confidence in the analyses. The real gem is the fact that it places
T. rex
right alongside the two birds in the sample (the chicken and the ostrich). In fact, so close is their relationship that a sophisticated statistical analysis is unable to distinguish between the three of them. More intriguingly, it includes the alligator in this group, well separated from the other reptile in the sample (the humble lizard). Alligators, it seems, might also be dinosaurs in disguise – though, to be fair, we know that the crocodile family is very old (it overlapped in time with the dinosaurs
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for the better part of 150 million years).

Although anatomists have come to suspect that birds and dinosaurs share a common ancestry, this example is still a reminder that appearances can easily deceive. Just because two species look very different, it does not necessarily mean that they are unrelated. The big surprise of the 1980s was the discovery that, despite the radical difference in appearance, we humans share a recent common ancestry with the chimpanzees (and to a lesser extent the gorilla). In fact, the two subspecies of gorilla (the eastern and western) are genetically more different from each other than humans are from chimpanzees. That’s a sobering thought. Previously, taxonomists had assumed, on the basis of solid anatomy, that chimpanzees, gorillas and orang utans formed one ape family and humans a separate one, with a common ancestry around eighteen million years ago. The genetic evidence revealed that, in reality, it was the orang utan that was the odd one out –it did indeed share a common ancestry eighteen million years ago with the other great apes, but that was long before the three African ape lineages (human, chimpanzee and gorilla) appeared on the evolutionary scene.

Nothing is more contentious in the museum world than the hundreds of thousands of human skeletons that lie within their vaults. What has made these bones especially contentious is the fact that most of them come from native peoples in countries where the aboriginal inhabitants have long been oppressed into the margins of modern society. And it is not always just bones. It’s barely a decade since
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the Glasgow Museums repatriated a ‘Ghost Dance Shirt’ that had been taken from the body of a Sioux Indian after what was probably one of the least savoury incidents in American history, the infamous Battle of Wounded Knee in 1890.

However, few cases have been quite as curious as that of Kennewick Man. Discovered by chance in 1996 on the bed of the Columbia River, in Washington State in the USA’s northwest, this virtually complete male skeleton very quickly aroused controversy when archaeologist Jim Chatters, into whose hands the bones were consigned for analysis, declared them to be about nine thousand years old – and probably of European origin. As the oldest complete human skeleton ever found in the Americas, that was inflammatory stuff. As it happens, there is now quite compelling evidence to suggest that the earliest inhabitants of North America did in fact come from Europe (the vicinity of Spain, as it happens) sometime around twenty thousand years ago. It seems that they were swamped five thousand or so years later by the arrival of the ancestors of the modern Native Americans who came from Siberia across the Bering Strait... But that’s another story.

Native Americans, like Australian Aboriginals, have at times been very vociferous in demanding the return of all bones for reburial, on two separate grounds. One is an understandable cultural belief that the ancestors should be treated with due respect and buried properly in the safekeeping of their descendants. Many of the Native American skeletons in US museums were, not to put too fine a point on it, removed from ancient tribal burial grounds without so much as a by-your-leave. The other is the rather more murky issue of land claims. Nowadays,
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showing that your tribe lived at a site in earlier times gives considerable grist to the land-rights mill, and can be very big business if prior ownership of the land then allows you to build a casino there.

Now, as it happened, the land that Kennewick Man was found on was federal land under the control of the US Army. They promptly impounded the bones, but, when presented with a request for repatriation to a consortium of local tribes, agreed to hand them over. However, a group of anthropologists sued to prevent the bones being repatriated for reburial until there had been an opportunity to study them in more detail. That was in October 1998, and the case remains unresolved. One unexpected benefit to come out of all this is that, perhaps because of all this furore and the need to figure out just who he was, Kennewick Man’s bones have been studied in more excruciating detail than almost any other human remains other than genuine fossils. After all, if he really is European, Kennewick Man has rather interesting implications for the history of American colonisation.

However, the issue raises the tricky question of who has rights over human remains. In one sense, the older the bones are, the more they belong to all of us. But even the most recent historical specimens can tell us a great deal about the story of our collective history, the patterns of migration, the successes and failures of our species, the trials and tribulations of human experience through the ages. Nor is this simply a matter of a quick anatomical description, or extracting a scrap of bone to analyse its DNA. Much of what we can do depends on the questions we have learned to ask, and these become more sophisticated as our knowledge grows. As every amateur archae-
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ologist knows, much was lost for ever by poor excavation techniques even as recently as the 1940s. Moreover, the questions of yesteryear often prove to be naïve and misleading. And much depends on the discovery of new technology: DNA analysis has revolutionised our understanding of many aspects of history in the last decade or so. But we can only learn from this if the bones are there to study.

Many have complained that much of the pressure for repatriation has come from earnest but politically motivated western intellectuals, rather than from native peoples themselves. Museums – often confused about their own role in modern society, and sometimes under pressure from governments – have been over-anxious to be seen to be doing the right thing. But the outcome has sometimes been comical. One attempt to repatriate and bury four Inuit bodies that had been marooned in a major US institution, for example, was greeted with embarrassment by the Greenland community who were forced to accept them. What have they got to do with us, they asked?

Although the battle for bones has often been seen as a conflict between western science and the sensitivities and rights of native peoples, it need not always be so polarised. When the contents of the burial vaults from Christ Church, Spitalfields, in London were removed to the Natural History Museum, researchers were able to integrate their study of the skeletons with detailed family history information – sometimes even portraits – provided by descendants who took great delight in being part of the process. If more was done to persuade the communities concerned to be part of the process of science in exploring and celebrating their own histories rather than locking those his-
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tories away from sight, we might all benefit. More importantly, it might even lead to a wider understanding of Darwin’s theory of evolution.
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Our history is a long one, stretching back some six million years to the point at which our ancestors parted company with the other members of the African great apes, the biological family to which we humans belong. The passage from then to now, however, has been far from simple or straightforward. There were many blind alleys that led nowhere in the end, even though some of them prospered for many hundreds of thousands of years before going extinct – the many australopithecines (the apemen that diversified into more than a dozen different species between six and two million years ago), the early
Homo
erectus
species that migrated out of Africa and colonised Asia as far east as modern Beijing, the iconic Neanderthals of Europe. There were, equally, many moments when the fragile lineage that eventually gave rise to us teetered on the brink of extinction. The genetic evidence now indicates that all modern humans are descended from as few as five thousand breeding women who lived around two hundred thousand years ago in Africa. So small a breeding population could easily have disappeared without trace.

In fact, we live in rather privileged times. We are the
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only species of our lineage now in existence. But in fact this is the first time in our lineage’s six-million-year history that this has been true. The last ten thousand years or so have been unusual in having only one species of our lineage alive: prior to that, there have always been several, sometimes as many as six. Many of these now-extinct species survived a great deal longer than we humans have done so far. More sobering is the fact that some of the now extinct members of our family survived late enough to be within handshaking distance of us. The last Neanderthals died out in Europe only twenty-eight thousand years ago. The last
erectus
hominids died out in China some time after sixty thousand years ago. And on the Indonesian island of Flores, a diminutive member of this group may have survived until as recently as twelve thousand years ago. Just who were these relatives of ours?

We will never know her name. Indeed, we will never know whether she even had a name. But when her remains were unearthed in 2004 in a cave on the Indonesian island of Flores, she caused the kind of stir that we normally associate with Hollywood film stars. She died in complete obscurity around eighteen thousand years ago, only to be catapulted into glittering fame by a chance discovery.

Soon nicknamed ‘The Hobbit’, she and her kind (in fact, the remains of as many as five different individuals were unearthed altogether) excited the palaeoanthropol-ogy community and sent the world’s media into something of a spin amid claims that the story of human evolution would have to be rewritten.
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In fact, the truth has turned out to be a little more pro-saic, though just as remarkable for all that. The Hobbit was certainly distinctive enough to be given a new species name,
Homo floresiensis
, after her home island. But what made her so newsworthy was not that she was one of our direct ancestors – in fact, we probably last shared a common ancestor with her about a million and a half years ago – but the fact that her kind had survived at all for so long.

Our current understanding of human evolution, based on the fossil evidence we have, goes something like this. After the long haul of the ‘apeman’ phase (typified by the famous 3,300,000-year-old ‘Lucy’ skeleton from Ethiopia, famously named after the Beatles’ song ‘Lucy in the Sky with Diamonds’ that happened to be playing on the exca-vator’s tape-recorder when her bones were unearthed), our ancestors underwent a relatively rapid gearshift into a more obviously humanlike form known to scientists as
Homo erectus
(literally ‘erect man’) some time just short of 1.5 million years ago. Though brain size increased quite a bit from the 350cc typical of its earlier apelike species, it was still a long way off the relatively massive 1250cc that we find in modern humans. What we do find, however, is a new body shape that has the same long legs, narrow hips and barrel chest that modern humans have –features associated with a more efficient form of striding walk that was good for covering long distances in a nomadic, migratory lifestyle.