March 2004

Image of 'Mapping Human History' by Steve Olson

March's choice for Book of the Month is Steve Olson's "Mapping Human History: Genes, Race, and Our Common Origins." In essence this is similar to other books that are concerned with the question of human ancestry with respect to new finds in genetics. Olson takes this a bit further and discusses the other topics which have been used to discuss human history, like linguistics and the spread of agriculture.

Olson's introduction does a decent job of setting us up for what we're going to experience in the rest of this book. He explores how we are so varied in our appearance, but wonders why we are so similar genetically. His intention with this book is to take us through the history of humans, stopping at points along the way to help provide an explanation for this apparent mispairing between physical appearance and genetic similarity.

Africa

The End of Evolution: The African Origins of Modern Humans

The most natural place for any book on human history is in Africa, the birthplace of humanity. He starts his story with a group of people known colloquially as the Bushmen. They call themselves the Ju/'hoansi or !Kung San. The significance of these people is that they are the original people from southern Africa. Despite being there "first," they have been treated many different ways, most of them not so kindly. Olson really dives into the question of diversity in appearance in this chapter, mentioning basic biology information about how cells are passed on, chromosomes carrying genes and what not, so I don't feel the need to reprint it here. Besides, many people probably already have an idea of the basic concept. He does make one good point though, which is a basis of this book: DNA, the blueprint of life, can tell us about ourselves, and our past.

After his brief bit about DNA, Olson talks about what he considers the four most significant aspects of human evolution, all of which took place in Africa, and he suggests happened within 500 miles of the Earths equator:

About 6 million years ago, a single population of apes diverged, into two, one which would lead to modern chimpanzees, the other to us.
About 4 million years ago, s significant change in locomotion, bipediality, helps free up our hands, suggesting we had more freedom to use them in other ways.
About 2 million years ago, this freedom of our hands led to the development of tools which were then used to help get food, specifically helping to carve meat from carcasses.
Then, sometime between 100 and 200 thousand years ago, our species, Homo sapiens, on the scene.

Up to this point, this has all been based on what we've discovered in the fossil record. He goes on to describe the uniqueness of extant humans, noting that while we are now the only representative of our genus, at many points in human history, more than one species of human has lived at the same time. We may have even lived in the same places at the same time. We certainly did live in the same place as Neandertals (Homo neandertalensis). The point here is that general convention holds that humans are an african species. Not all paleoanthropologists hold this view. Some accept a concept called multi-regionalism, where the current form of Homo sapiens developed independently from closely related but geographically isolated ancestors. Some contend that this helps explain our "racial" differences. This view has come under much scrutiny, however, in light of genetic research.

At this point, Olson introduces the concept of Mitochondrial Eve. This concept uses the inheritance properties of mitochondria, and builds a family tree based on how different one persons mitochondrial DNA are from someone else's. A brief departure is needed here to explain the concept. Mitochondria are in everyone's DNA, but they aren't native to humans. Convention has it that they are the descendants of bacteria, which are symbiotic now with our cells, as well as many other life forms. Mitochondria provide energy four our cells, and when people reproduce, they send copies of mitochondrial DNA, which changes at a fairly regular and predictable fashion. The catch here is that they are only passed on through maternal lines. Now, since these mitochondrial DNA are predictable and inherited only from the mother, you can compare mtDNA (mitochondrial DNA) from any two people, and the more similar they are, the closer they are in relation. Extensive studies have shown that mitochondrial Eve existed about 100-200 thousand years ago, right when our species appeared in Africa. What's more, everyone can trace their ancestry back to her, which is why the multi-regional concept is no longer in favor.

Individuals and Groups: The Divergence of Modern Humans

This chapter deals with the concept of race. As we found out in the previous chapter, humans are very similar genetically. In fact, you can take any to humans on Earth, and compare their DNA; it'd still be more similar than two chimps from the same troupe in Africa. The important message in this section is that our cultural bias for race is unfounded; we're all either Africans, or descendants of them. An interesting point in this chapter is how Olson talks about the similarities between neighboring groups of people. His example looks at people that can be found between the cities of Madrid and Beijing, traveling east. Those close to each other have degrees of similarity, more so than people farther away. So while we may find differences in each other, there aren't any specific differences that any one group can claim. Next, Olson takes on a numbers game, showing us just how closely related to each other we really are. If you were to look at a list of your family tree going back to about 10 generations or so, (In Olson's example, he's using a 20 year generation, so about 200 years), everyone now living would had 1024 great-great-great-great-great-great-great-great-grandparents. Going back another 10 generations, those ancestors would also have 1024 ancestors. Go back one further, and you'll have another 1024 for each of THOSE ancestors (1024X1024X1024, or more than a billion ancestors.) This puts us to about the year 1400, when the worldwide population was about 375 million. Clearly there is a discrepancy. Is our number wrong, or were there more people living than we think? Neither. Undoubtedly some of the names on the family tree we've generated are the same, because at some point, there is a sharing of ancestors. It's very difficult to find the pedigree of every human on Earth, but the numbers support just how closely related we are, even showing how related we are to each other.

The African Diaspora and the Genetic Unity of Modern Humans

This chapter details the many migrations (forced or voluntary) of people from Africa to other parts of the world, and how color has been perceived as an indicator of such things as intelligence or susceptibility to disease.

He starts with briefly talking about migrations out of Africa around 100,000 years or so, then goes into how Africa has been a source of slaves. "The slave trade," says Olson, "was responsible for one of the largest human migrations the world has ever seen." Between Europe and the New World, millions of Africans, primarily from central Africa, were brought as slaves, and to a large degree their descendants have continued to live there. Being such a prevalent part of society, slaves definitely had an impact on society, and society did its part in defining the "attributes" of slaves. Because of their position, as slaves, it has been easy for people in the past (and still in the present) to denigrate slaves and their descendants as being "lower." This led to discrimination of any "race" other than Europeans; up until recently (1967), Olson points out, interracial marriages in America were illegal. An unfortunate contributor to this was science, ranging anywhere from classifying non-whites as being part of subraces of Homo sapiens and describing them in a negative light, to skewing IQ results pointing to European intelligence superiority.

Olson finishes this chapter, and this section about Africa talking about a few things that are present in a few populations of specific humans, such as Tay-Sachs disease, or Sickle-Cell Anemia. Despite that there are some genetic diseases, they aren't a basis for defining races in humans.

Middle East

Encounters with the Other: Modern Humans and Neandertals in the Middle East

Olson opens up this section and chapter talking about a cave in modern-day Israel known as Skuhl. This particular cave is significant for a few reasons. When discovered and described in 1932, eleven bodies were recovered, one of the largest prehistoric collections of fossil modern humans ever found. Near to this cave in a placed called Tabun, Neandertal remains were found. Most surprisingly was that the fossils found at Tabun ranged in age from about 2000,000 years old to about 40,000, while those of Skhul were about 100,000 years od. This suggests that modern humans and Neandertals were living in this region roughly at the same time. Naturally this led to questions about how close in contact they were: did they fight with each other, mate with each other, go about their separate ways?

Next comes a brief history of the Neandertals and their portrayal over time, from brutish, thick-skulled barbarians, to something close, but not too close, to modern humans. The role of Neandertals in relation to modern humans (Homo sapiens) has changed over time. Some anthropologists have suggested that they were the ancestors of Europeans, although there is little evidence to support this idea. The only definitive proof to show that modern humans were from separate stock than Neandertals was to find genetic material from a Neandertal. Not an easy task. If they are able to find Neandertal DNA, and that DNA was mitochondrial DNA it would help determine if modern humans are in any way related to Neandertals. That is precisely what has been found, so it pretty much closes the book on multi-regional evolution, at least as far as Europeans go. So, now that we're not from them, would our ancestors still have mated? If they did, could they have offspring? The jury is still out on that, but what we do know is that there isn't any Neandertal mtDNA in any modern human population, so if they did mate and breed, none survived to contribute to our modern gene pool.

The next question regarding the mystery of the Neandertals is why they went extinct. They were certainly very well adapted for living in arctic Europe during the Ice Age. Did modern humans kill them off, or were we just better hunters? Was something else to blame? Modern humans had a more elaborate tool kit than that of the Neandertals, but some evidence suggests that close to their and, they were adopting some of the tool styles being imported in from Africa. Neandertals had big brains, in some cases even larger than modern humans, so it might not have been smarts that spelled their demise. Another proposed idea suggests that simple language and communication held the key of success for modern humans. The elaborate tools they were using might have needed just as elaborate directions to be crafted. It might have been the development of language that made the big shift of power possible.

Agriculture, Civilization, and the Emergence of Ethnicity

This chapter discusses the development of agriculture, which seemed to have first taken place in the Middle East (although it has appeared in other regions completely independently). Olson starts with a little jaunt into the biblical stories behind the ancient city of Jericho, considered by archaeologists as the formal birthplace of agriculture. No doubt the advent of agriculture was perhaps one of the greatest and most important events in human prehistory.

Why agriculture? Humans had been living by the hunter/gatherer method for millennia, so why the shift to a completely new method of obtaining food? One trend seems to be in the increasing population of human groups. Prior to agriculture being developed, most human populations consisted of groups called bands, which primarily consisted of closely related families, and ranged in size from 10 to 50 people. These bands were then associated with other bands which could form a loose grouping called a tribe. Mating and pairing usually took place within a band, but some also took place between bands that were part of the same tribes. This general plan of human society existed for most of human history (and to some degree still does today). But, some time around 12,000 years ago, something changed. Bands and tribes were generally nomadic, following game and exploiting resources wherever they went, but this new change started a more sedentary lifestyle. More permanent structures were being built, and more tools were invented to process food year round. One early culture that adopted this lifestyle were the Natufians, and one of their earliest locations was Jericho. Now, Jericho seemed to be a seasonal camp, at first, but about 10,000 years ago things became more permanent. The remains in the area suggest that early Jericho had a population of a few hundred people. People like to think of Jericho as the world's oldest city, and in some ways it is, but in fact there were other towns near Jericho. Jericho just happened to be "one of the largest and most sophisticated."

Many people have tried to pin down an explanation for why agriculture developed in the Middle East and elsewhere in the world. So far, the only things we know is that agriculture coincided with the end of an Ice Age, and growing numbers of humans, which may or may not have outgrown the carrying capacity of the land they lived on. Olson ends this chapter exploring the concept that states and nations are simply just expanded versions of tribes and bands.

God's People: A Genetic History of the Jews

This chapter explores one group in particular from the Middle East: the Jews. He starts out by giving a brief history of the area known as Palestine, then moves into the genetic trends found within the Jews. Perhaps the most interesting thing about the genetics of the Jews is something called Aaron's Y chromosome. Within Judaism, all of the male descendants of Moses' brother Aaron hold the position of high priests, known as the kohanim. This transferred to last names such as Cohen, Cohn, etc, derivatives of kohan. Y chromosomes are what make males, males, and they're passed from father to son. The significance of Aaron's Y chromosome is that half of all currently living priests within Judaism have the same set of markers on the Y chromosome. This is known as the Cohen Modal Haplotype, and a further interesting bit concerning it comes from southern Africa, in a tribe of people called the Lemba. The Lemba are of Jewish faith, and claim to be one of the twelve lost tribes of Israel, a result of the Roman Diaspora. The cool thing here is that there seems to be some truth to this claim; a large number of the Lemba have the Cohen Modal Haplotype. This chapter also mentions a group of people known as the Samaritans, a group with many similarities to the Jews, but not accepted as Jewish. The Samaritans follow strict guidelines from the Torah, especially those concerning the marriage. As a result, they've grown into a small population that has ancestry with only 5 male lineages, due to inbreeding. While they do have a few genetic problems, such as congenital deafness, overall, they just look like a bunch of very closely related family members.

Asia and Australia

The Great Migration: To Asia and Beyond

This chapter starts off with Olson sitting in with Chinese scientists, examining a curious collection of mummies found in central Asia, in the Tarim Basin. The mummies found here provide an unusual glimpse into the relatively distant past, as some of the mummies have clearly European characteristics (such as light colored hair and sharper noses). These rare mummies present a new study of genetics for people in the western parts of China, who claim a nationalistic independence from other Chinese, pointing to a shared European ancestry. This is important genetic research, because it lends insight into the migration out of Africa and into Asia and subsequently the rest of the world. Just how people moved from Africa to Asia isn't clear. They could have merely moved more easterly as they arrived in the Middle East, migrated along the coast of the Red Sea, or might have even used boats to travel the short distance across the Strait of Bab al Mandeb, the narrow part between the African country of Djibouti, and the Asian country of Yemen, which is on the Arabian Peninsula. We know humans lived along the coastline, as there are sites with shells deposited in piles, considered associated with humans. Genetic evidence points to a separate migration between those humans in the Middle East and those in the southern part of the Arabian peninsula, which in turn supports a possible migration across the Sinai peninsula. Whatever the case, humans quickly spread into Asia, then into Australia, as evidence indicates a relationship between the large animals of Australia going extinct, and the arrival of humans between 60,000 and 65,000 years ago. By about 40,000 years ago, humans were in southeastern Asia; by 26,000 they were around present day Beijing, China.

For many years, paleoanthropologists both outside of China, and especially in China have accepted a view that the Asians, and Chinese in particular developed separately from the African population of Homo sapiens, most likely from Homo erectus. In order to determine if this view is correct, geneticist Li Jin studied the Y chromosome of 10,000 Chinese men. If modern humans did indeed have ancestry separate from African populations, there would be an indication in the Y chromosome; it'd be different than ones that come from Africa. There weren't any differences found, which indicates that Chinese, as well as other Asians most likely have ancestry with the African populations. Jin's study also showed a general direction of movement of humans into Asia, a trend from south to the north. These finds are troubling to many Chinese, who have a proud heritage; many Chinese claim ancestry with an ancient emperor named Huang-Ti. As we saw before, they very well may have ancestry with him involved, but the genetic evidence tells us that Huang-Ti, if he existed, had ancestors from Africa.

Throughout history, many things have been used to try to distinguish Asians as a race, such as the presence of epicanthal folds (fleshy flap of skin over the upper eyelid) and flat noses, both of which are considered as adaptations to cold weather. But these aren't found in all Asians, just the ones that live in the northern part of Asia. The point here is that Asia has a diverse, and complex human history, which details more of the similarities of humans than differences.

Sprung from a Common Source: Genes and Languages

This chapter was probably the hardest one for me to follow. Basically, he discusses the use of linguistics to try and establish human relationships and ancestry. This is a very difficult task, but it seems at least superficially reasonable. Languages evolve as populations do, and there are clear relationships between languages, for example the Romance languages (Spanish, French, Italian and Portuguese). They are distinct on their own, but many words sound very alike. In many cases, languages from neighboring regions tend to share more words than those farther apart; this seems pretty intuitive. Then you get into language families, such as the Indo-European family of languages, which includes the Romance languages. Olson talks about some major groups among the various continents, which is pretty interesting. Then he gets into the meat of what the linguists face: similarities between languages and differences. He makes a very valid point in discussing how some words that seem common to languages is more just a cultural artifact than an ancestral one. His example is the word "okay." Most people around the world now use this expression in the same fashion all over the world. You can hear "okay" with African Bushmen, or Japanese businessmen, and it carries the same meaning. However, it doesn't mean that the two languages are related; they aren't closely related at all. I think the major point with this chapter is that linguistics might be a useful tool in helping determine relatedness, but it might not be so great at determining ancestry.

Europe

Who Are the Europeans?

This chapter focuses on the history of the Europeans, and especially how concepts of their origins has changed over time. Western scientists, unfortunately, have a tradition of using science to make determinations about the superiority of Europeans to other groups of people around the world. This has, in the past, played a part in anthropology and archaeology, and has led to many incorrect notions of European humans. An example of this comes from the general term for the "race" that most Europeans are generally considered to be a part of. It typically refers to pretty much any white European, but the list of traits that define Caucasians includes people from India, some of whom have very dark skin, black hair, and brown eyes. Recent studies of mitochondrial DNA show that there is also a flow of Europeans out of and into India, which explains the correlation of shared features.

Geographically speaking, Europe is diverse, and this has lead to a diversification of groups within Europe. One new area of science discusses how the role of agriculture developed in Europe. Olson goes into great detail of this complex wave of society that helped contribute to Europe's mixture of cultures, many of which are similar, others which are quite different. Olson continues the story of genetic mixing that's going on even today in his next chapter.

Immigration and the Future of Europe

In the previous chapter, Olson talks about how the influx of genetic material for human in Europe from the Middle East has created a varied population, which gives insight into the human history of Europe. Here he talks about immigration in Europe right now, which is leading to further genetic mixing from people around the world. His focus starts in France, which has a very liberal immigration program, but is considered by some immigrants as still very racist, in particular against Arabs. The influx of immigrants is changing the demographics of the French populace, despite that France itself doesn't keep tabs on the different groups immigrating into the country. The use of France, as well as brief bits about the immigration policies of other European countries is a segue into the European concept of race. He goes into how the concept of race has been viewed by European cultures starting with the Greeks and Romans, and develops the history over the next few pages, ending to the early 20^th Century views of some scientists. After this, he talks about the different groups that have contributed genetic material into France specifically, such as the Celts and the Huns. All of this information is brought into context by examining the statistics of immigration and population growth, and possible results at some point in the future. Both seem to indicate that diversity in Europe is now increasing at a rate that hasn't been seen since the early waves of agriculture began flowing into Europe 9000 years ago. Olson concludes that this will change the concept of "race" in Europe even more, as the lines dividing different groups commonly held as separate grow more blurry.

The Americas

The Settlement of the Americas

This last section deals with the last major continents to receive human immigrants: North and South America. This first chapter deals with a very controversial find in Washington State known as Kennewick Man. This find raised a lot of questions with its discovery. The features give Kennewick Man a caucasian look (some have likened him to actor Patrick Stewart). A stone projectile found in his hip indicates that this wasn't just some unlucky white guy that had been killed, and carbon-dating reaffirmed this by giving a date for him at 9,500 years old. Kennewick Man is one of the oldest human remains ever found in the Americas, and he immediately was claimed by Native Americans, using the new NAGPRA (North American Graves Protection Act) laws. This means that any remains found on federal land can be claimed by Native Americans if they can show "cultural affiliation" through any "geographical, kinship, biological, archaeological, anthropological, linguistic, folklore, oral tradition, historical, or other relative" evidence of a connection to the remains. The old age for Kennewick Man makes it very difficult to establish tribal affiliation, and its European-like features make it doubly hard to find a relationship to modern Native Americans, but despite this the federal government went along with the claims. This created somewhat of a furor in the scientific community, because it meant that they could no longer study this very rare find, and try to figure out what makes it so unique.

The notion that the Americas were populated from Asia is surprisingly old, going back more than 400 years ago. Archaeological evidence along with anthropological data seems to help confirm this notion, and presently there may have been at least 3 waves of migration into the Americas via a land bridge over the Bering Strait. Olson talks about the Clovis culture, and how science has come to view the movements of humans into the Americas. Clovis is generally considered to be the oldest culture in the Americas, but some sites suggest cultures that are prior to Clovis, in particular Monteverde in Chile. Is there a genetic relationship between Native Americans and Asians, though, that agrees with archaeological information? Olson examines this in his next chapter.

The Burden of Knowledge: Native Americans and the Human Genome Diversity Project

Olson starts this chapter describing the Human Genome Diversity Project, suggested by a scientist named Luca Cavalli-Sforza. His paper called for the collection of data from indigenous groups before their populations were destroyed by genetic mixing. This is important, as it can give insight into human history; it can map how human populations have moved from place to place around the world. This seems a reasonable request, but it was met with very harsh backlash from Native American groups, who claimed that the information could be used to discriminate people genetically. As god as Cavalli-Sforzas intentions were, this is a valid concern, and as a result, it has been very difficult in obtaining information from Native American groups. Along with the genetic information and how its interpreted, is how the information will relate to beliefs held by Native American groups. Native American creation stories typically hold that specific tribes were created in the Americas; there isn't a mention of a migration from Asia or anywhere else. This makes some Native Americans feel that its another attempt to take cultural beliefs away from them. This has lead to highly refined methods of acquiring genetic material information. Instead of recording the exact individuals samples are acquired from, only the nationality they claim is mention, and it is always done only when there is informed consent. Some groups have also put stipulations on the genetic tests, such as not allowing researchers to show relationships with their tribe to any other groups. But, at least we get the information to study human diversity.

The World

The End of Race: Hawaii and the Mixing of Peoples

This final chapter in Olson's book discusses the diversity that exists in Hawaii, probably one of the highest concentrations of mixed human genetic material anywhere on Earth. He starts with a little history about Captain Cook's arrival on the islands and how how the European contact impacted the native Hawaiians. Many Hawaiians have a complex hodgepodge of ancestry, as many different groups have come to the island in the past, most since colonization by the Europeans and their formation of sugar plantations. Such groups include Chinese, Japanese, Filipinos, Spanish, Germans and Russians. Even before it was discovered by Cook in the late 1700's, there were at least two migrations of people from Asia, in particular the Marquesas and from Tahiti. Each group brought tAnd the man and his wife were both naked and were not ashamed. Their own traditions, which developed into a unique culture. Despite this mixed heritage, and the common instances of intermarriage between ethnic groups, there is still a wave of Native Hawaiians pushing for an ethnic sovereignty. But what makes one a Hawaiian, with all of this genetic mixture?

Summary

I highly recommend this book to anyone interested in the question of where humans come from. This is also a good book for people interested in seeing how closely related we are to everyone else in the world. Olson has a great way of bringing together topics from one chapter and resurfacing it appropriately in a later chapter. His research seems sound, and he seems to have a genuine interest in the topic he is writing about, which is reflected in the detail he's given in the text. Overall, a joyful read.