DNA News Page 16
Home    Back

-- 400,000-Year-Old Mitochondrial DNA Surprises Scientists - 12/05/13
-- Blue eyes, dark skin: How European hunter-gatherer looked, 7,000-year-old genome shows 1/26/14
-- Ancient DNA unravels Europe's genetic diversity - 10/10/13
-- Rare Human Y Chromosome Is More than 300,000 Years Old - 3/08/13
-- Most Europeans share recent ancestors - 5/07/13
-- European Women at Root of Ashkenazi Family Tree - 10/08/13
-- New Low-Cost Technique Isolates Ancient DNA - 10/29/13
-- 45,000-Year-Old Genome of Modern Human Sequenced - 10/23/14
-- DNA Results Reveal Details of Puerto Rican History - 7/25/14
-- Genes and Race: The Distant Footfalls of Evidence - 5/13/14

 400,000-Year-Old Mitochondrial DNA Surprises Scientists

December 05, 2013 

LEIPZIG, GERMANY—It had been thought that the hominins that lived in Spain’s cave of Sima de los Huesos were early Neanderthals or members of Homo heidelbergensis. But a 400,000-year-old femur from the cave has yielded mitochondrial DNA, which is inherited only through the female line, and it links the residents more closely to the Denisovans than to Neanderthals or modern humans. “This really raises more questions than it answers,” said Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology. He thinks that the Sima de los Huesos hominins may have been a founder population that gave rise to both Neanderthals and Denisovans. Pääbo’s team will attempt to extract nuclear DNA, inherited from both parents, from the bone samples. “My hope is, of course, eventually we will not bring turmoil but clarity to this world,” he added.


 Blue eyes, dark skin

How European hunter-gatherer looked, 7,000-year-old genome shows

January 26, 2014     Spanish National Research Council (CSIC)

La Braña 1, the name used to baptize a 7,000 years old individual from the Mesolithic Period, whose remains were recovered at La Braña-Arintero site in Valdelugueros (León, Spain), had blue eyes and dark skin. These details are the result of a study conducted by Carles Lalueza-Fox, researcher from the Spanish National Research Council (CSIC), in collaboration with the Centre for GeoGenetics (Denmark). La Braña 1 represents the first recovered genome of an European hunter-gatherer.

The research is published in Nature.

The Mesolithic, a period that lasted from 10,000 to 5,000 years ago (between the Paleolithic and the Neolithic), ends with the advent of agriculture and livestock farming, coming from the Middle-East. The arrival of the Neolithic, with a carbohydrate-based diet and new pathogens transmitted by domesticated animals, entailed metabolic and immunological challenges that were reflected in genetic adaptations of post-Mesolithic populations. Among these is the ability to digest lactose, which La Braña individual could not do.

Lalueza-Fox states: "However, the biggest surprise was to discover that this individual possessed African versions in the genes that determine the light pigmentation of the current Europeans, which indicates that he had dark skin, although we can not know the exact shade."

CSIC researcher, who works at the Institute of Evolutionary Biology (a joint centre of CSIC and the University Pompeu Fabra (UPF), located in Barcelona, adds: "Even more surprising was to find that he possessed the genetic variations that produce blue eyes in current Europeans, resulting in a unique phenotype in a genome that is otherwise clearly northern European."

The study of the genome suggests that current populations nearest to La Braña 1 are in northern Europe, such as Sweden and Finland. In addition, the work points out that La Braña 1 has a common ancestor with the settlers of the Upper Paleolithic site of Mal'ta, located in Lake Baikal (Siberia), whose genome was recovered a few months ago. Lalueza-Fox concludes: "These data indicate that there is genetic continuity in the populations of central and western Eurasia. In fact, these data are consistent with the archeological remains, as in other excavations in Europe and Russia, including the site of Mal'ta, anthropomorphic figures -called Paleolithic Venus- have been recovered and they are very similar to each other."

DNA with an "exceptional" preservation

La Braña-Arintero site was discovered by chance in 2006 and excavated by Julio Manuel Vidal Encinas, archeologist of the Council of Castilla y León. The cave, located in a cold mountainous area with a steady temperature and 1,500 meters below the sea level, contributed to the "exceptional" preservation of the DNA from two individuals found inside, and they were called La Braña 1 and La Braña 2.

According to Iñigo Olalde, lead author of the study, "the intention of the team is to try to recover the genome of the individual called La Braña 2, which is worse preserved, in order to keep obtaining information about the genetic characteristics of these early Europeans."

Story Source:

The above story is based on materials provided by Spanish National Research Council (CSIC). Note: Materials may be edited for content and length.

Journal Reference:

1.Iñigo Olalde, Morten E. Allentoft, Federico Sánchez-Quinto, Gabriel Santpere, Charleston W. K. Chiang, Michael DeGiorgio, Javier Prado-Martinez, Juan Antonio Rodríguez, Simon Rasmussen, Javier Quilez, Oscar Ramírez, Urko M. Marigorta, Marcos Fernández-Callejo, María Encina Prada, Julio Manuel Vidal Encinas, Rasmus Nielsen, Mihai G. Netea, John Novembre, Richard A. Sturm, Pardis Sabeti, Tomàs Marquès-Bonet, Arcadi Navarro, Eske Willerslev, Carles Lalueza-Fox. Derived immune and ancestral pigmentation alleles in a 7,000-year-old Mesolithic European. Nature, 2014; DOI: 10.1038/nature12960


 Ancient DNA unravels Europe's genetic diversity

October 10, 2013    Source:University of Adelaide

Ancient DNA recovered from a time series of skeletons in Germany spanning 4,000 years of prehistory has been used to reconstruct the first detailed genetic history of modern-day Europeans.
Credit: © Malgorzata Kistryn / Fotolia[Click to enlarge image] Ancient DNA recovered from a time series of skeletons in Germany spanning 4,000 years of prehistory has been used to reconstruct the first detailed genetic history of modern-day Europeans.Credit: © Malgorzata Kistryn / Fotolia
Ancient DNA recovered from a time series of skeletons in Germany spanning 4,000 years of prehistory has been used to reconstruct the first detailed genetic history of modern-day Europeans.

The study, published today in Science, reveals dramatic population changes with waves of prehistoric migration, not only from the accepted path via the Near East, but also from Western and Eastern Europe.

The research was a collaboration between the Australian Centre for Ancient DNA (ACAD), at the University of Adelaide, researchers from the University of Mainz, the State Heritage Museum in Halle (Germany), and National Geographic Society's Genographic Project. The teams used mitochondrial DNA (maternally inherited DNA) extracted from bone and teeth samples from 364 prehistoric human skeletons ? ten times more than previous ancient DNA studies.

"This is the largest and most detailed genetic time series of Europe yet created, allowing us to establish a complete genetic chronology," says joint-lead author Dr Wolfgang Haak of ACAD. "Focussing on this small but highly important geographic region meant we could generate a gapless record, and directly observe genetic changes in 'real-time' from 7,500 to 3,500 years ago, from the earliest farmers to the early Bronze Age."

"Our study shows that a simple mix of indigenous hunter-gatherers and the incoming Near Eastern farmers cannot explain the modern-day diversity alone," says joint-lead author Guido Brandt, PhD candidate at the University of Mainz. "The genetic results are much more complex than that. Instead, we found that two particular cultures at the brink of the Bronze Age 4,200 years ago had a marked role in the formation of Central Europe's genetic makeup."

Professor Kurt Alt (University of Mainz) says: "What is intriguing is that the genetic signals can be directly compared with the changes in material culture seen in the archaeological record. It is fascinating to see genetic changes when certain cultures expanded vastly, clearly revealing interactions across very large distances." These included migrations from both Western and Eastern Europe towards the end of the Stone Age, through expanding cultures such as the Bell Beaker and the Corded Ware (named after their pots).

"This transect through time has produced a wealth of information about the genetic history of modern Europeans," says ACAD Director Professor Alan Cooper. "There was a period of stasis after farming became established and suitable areas were settled, and then sudden turnovers during less stable times or when economic factors changed, such as the increasing importance of metal ores and secondary farming products. While the genetic signal of the first farming populations becomes increasingly diluted over time, we see the original hunter-gatherers make a surprising comeback."

Dr Haak says: "None of the dynamic changes we observed could have been inferred from modern-day genetic data alone, highlighting the potential power of combining ancient DNA studies with archaeology to reconstruct human evolutionary history." The international team has been working closely on the genetic prehistory of Europeans for the past 7-8 years and is currently applying powerful new technologies to generate genomic data from the specimens.

Story Source: The above story is based on materials provided by University of Adelaide. Note: Materials may be edited for content and length.

Journal Reference:

1.Guido Brandt, Wolfgang Haak, Christina J. Adler, Christina Roth, Anna Szécsényi-Nagy, Sarah Karimnia, Sabine Möller-Rieker, Harald Meller, Robert Ganslmeier, Susanne Friederich, Veit Dresely, Nicole Nicklisch, Joseph K. Pickrell, Frank Sirocko, David Reich, Alan Cooper, Kurt W. Alt, the Genographic Consortium. Ancient DNA Reveals Key Stages in the Formation of Central European Mitochondrial Genetic Diversity. Science, 2013 DOI: 10.1126/science.1241844

Cite This Page:

MLAAPAChicagoUniversity of Adelaide. "Ancient DNA unravels Europe's genetic diversity." ScienceDaily. ScienceDaily, 10 October 2013. <www.sciencedaily.com/releases/2013/10/131010142650.htm>.

 Rare Human Y Chromosome Is More than 300,000 Years Old

March 08, 2013

TUCSON, ARIZONA—Geneticists from the University of Arizona have identified an extremely rare Y chromosome that they say is the oldest-known branch of the human Y chromosome lineage tree. 

The discovery pushes back the most recent common ancestor for the lineage tree to 338,000 years ago, before the appearance of modern humans in the fossil record.

This particular Y chromosome came from an African-American man living in South Carolina who had sent a DNA sample to a consumer genetic testing company. His Y chromosome was eventually matched with 11 men from western Cameroon.  “And the sequences of those individuals are variable, so it’s not like they all descended from the same grandfather,” said Michael Hammer of the University of Arizona.

 “It is likely that other divergent lineages will be found, whether in Africa or among African-Americans in the U.S. and that some of these may further increase the age of the Y chromosome tree,” he added.


 Most Europeans share recent ancestors

Genetic sequences link far-flung populations and bear marks of historical events.

07 May 2013 Ewen Callaway

Whether they are a Serb and a Swiss, or a Finn and a Frenchman, any two Europeans are likely to have many common ancestors who lived around 1,000 years ago. A genomic survey of 2,257 people from 40 populations finds that people of European ancestry are more closely related to one another than previously thought, and could help to bring about new insights into European history.

The first efforts to trace human ancestry through DNA relied on ‘uniparental genetic markers’ — DNA sequences from the mitochondrial genome, which is inherited through mothers, or on the Y chromosome, which men inherit from their fathers.

Those studies captured the broad strokes of human history, such as Homo sapiens' migration out of Africa less than 100,000 years ago and their subsequent colonization of Europe and Asia. But uniparental markers do little to inform more recent history, in part because they represent only a single lineage in a family tree — such as a mother’s mother’s mother, and so on.

In recent years, researchers have looked to the rest of the genome — the DNA that can come from either parent — to understand ancestry. In the latest study, population geneticists Peter Ralph, now at the University of Southern California in Los Angeles, and Graham Coop, at the University of California, Davis, looked to the entire genome to reconstruct European ancestry. Their work is published today in PLoS Biology1.

The researchers' approach relies on the way in which genes are reshuffled each generation, when an individual forms new egg or sperm cells by mixing and matching the chromosomes he or she inherited from each parent. As a result of this process, a person’s genome is made from interspersed chunks of his or her ancestors’ chromosomes. The locations where DNA sequences are swapped are different each time, so that the uninterrupted segments a person passes down become shorter with each generation. For instance, the chunks of DNA shared between first cousins are longer than those shared between second, third and fourth cousins.

Gene-sequencing companies such as 23andMe, based in Mountain View, California, use this property to connect distant cousins enrolled in their databases. Ralph and Coop looked for even more distant relatives by identifying stretches of the genome shared by people living throughout Europe. By looking at the length of these chunks, the researchers were able to determine approximately when distant cousins’ common ancestor lived.

They found common ancestors from as recently as 500 years ago mainly within populations. Older stretches of DNA, however, connected more geographically distant Europeans.

The work also uncovered genetic signatures for key events in European history, such as the migration of the Huns into Eastern Europe in the fourth century, and the later rise of Slavic-speaking people there. Present-day inhabitants of Eastern European countries share many ancestors who lived around 1,500 years ago, Ralph and Coop found. Italians, meanwhile, are connected to other European populations mainly through individuals who lived more than 2,000 years ago, perhaps as a result of the country's geographic isolation.

Studies such as this one have the potential to solve longstanding historical questions, says Coop. It has been unclear, for instance, whether the expansion of Slavic languages was driven by migration of Slavic-speaking people, cultural diffusion or both. Genetic studies “can tell us how people moved, rather than just what’s in the written record”, Coop says. John Novembre, a population geneticist at the University of Chicago in Illinois, says that the study marks “a huge step in that direction”.


New Dates Could Alter Migration Route Out of Africa

13 September 2013

(Katerina Douka and Natural History Museum London)

OXFORD, ENGLAND—Radiocarbon dates have been obtained from marine shell beads unearthed at the Ksar Akil rock shelter in Lebanon. The beads, which were closely associated with the remains of a modern human young girl, are between 42,400 and 41,700 years old. Modern human fossils of a similar age have been found in Europe, but there have been few comparable discoveries in the Near East. It had been thought that early modern humans traveled out of Africa and through the Near East before arriving in Europe, but scholars think that these new dates indicate that people arrived in Europe and the Near East at roughly the same time, perhaps traveling along different routes. “It is possible that instead of the Near East being the single point of origin for modern humans heading for Europe, they may also have used other routes too. A maritime route across the Mediterranean has been proposed although evidence is scarce. A wealth of archaeological data now pinpoints the plains of Central Asia as a particularly important but relatively unknown region which requires further investigation,” said Katerina Douka of Oxford University.


 Genes Suggest European Women at Root of Ashkenazi Family Tree


Over the last 15 years geneticists have identified links between the world’s Jewish communities that point to a common ancestry as well as a common religion. Still, the origin of one of the most important Jewish populations, the Ashkenazim of Central and Eastern Europe, has remained a mystery.

A new genetic analysis has now filled in another piece of the origins puzzle, pointing to European women as the principal female founders, and to the Jewish community of the early Roman empire as the possible source of the Ashkenazi ancestors.

The finding establishes that the women who founded the Ashkenazi Jewish community of Europe were not from the Near East, as previously supposed, and reinforces the idea that many Jewish communities outside Israel were founded by single men who married and converted local women.

The study, published Tuesday in the journal Nature Communications, is based on a genetic analysis of maternal lineages. A team led by Martin B. Richards of the University of Huddersfield in England took a fresh look at Ashkenazi lineages by decoding the entire mitochondrial genomes of people from Europe and the Near East.

Earlier DNA studies showed that Jewish communities around the world had been founded by men whose Y chromosomes bore DNA patterns typically found in the Near East. But there was a surprise when geneticists turned to examine the women founders by analyzing mitochondrial DNA, a genetic element that is separate from the main human genome and inherited just through the female line.

Unlike the Y chromosomes, the mitochondrial DNA showed no common pattern. In several of the smaller Jewish communities it clearly resembled that of the surrounding population, suggesting a migration pattern in which the men had arrived single, perhaps as traders, and taken local wives who then converted to Judaism.

But it wasn’t clear whether or not this was true of the Ashkenazim. Mitochondrial DNA tends to change quite rapidly, or to drift, as geneticists say, and the Ashkenazi DNA has drifted so far it was hard to pinpoint its origin.

This uncertainty seemed to be resolved by a survey published in 2006. Its authors reported that the four most common mitochondrial DNA lineages among Ashkenazis came from the Near East, implying that just four Jewish women were the ancestresses of nearly half of today’s Ashkenazim. Under this scenario, it seemed more likely that the Ashkenazim were the result of a migration of whole communities of men and women together.

But decoding DNA was still quite expensive at that time and the authors of the 2006 survey analyzed only a short length of the mitochondrial DNA, containing just 1,000 or so of its 16,600 DNA units, in all their subjects.

The four mitochondrial lineages common among Ashkenazis are now very rare elsewhere in the Near East and Europe, making it hard to identify with certainty the lineages from which they originated.

With the entire mitochondrial genome in hand, Dr. Richards could draw up family trees with a much finer resolution than before. His trees show that the four major Ashkenazi lineages in fact form clusters within descent lines that were established in Europe some 10,000 to 20,000 years ago. The same is true of most of the minor lineages.
Continue reading the main story
Continue reading the main story
Continue reading the main story

“Thus the great majority of Ashkenazi maternal lineages were not brought from the Levant, as commonly supposed,” Dr. Richards and colleagues conclude in their paper. Overall, at least 80 percent of Ashkenazi maternal ancestry comes from women indigenous to Europe, and 8 percent from the Near East, with the rest uncertain, the researchers estimate.

Dr. Richards estimates that the four major lineages became incorporated into the Ashkenazi community at least 2,000 years ago. A large Jewish community flourished in Rome at this time and included many converts. This community could have been the source of both the Ashkenazim of Europe and the Sephardim of Spain and Portugal, given that the two groups have considerable genetic commonality, Dr. Richards said.

Doron M. Behar, of the Gene by Gene company in Houston and a co-author of the 2006 survey, said he disagreed with Dr. Richards’ conclusions but declined to explain his reasons, saying they had to appear first in a scientific journal.

David B. Goldstein, a geneticist at Duke University who first detected the similarity between the founding mothers of Jewish communities and their host populations, said the new analysis was well done but that the estimate of 80 percent European origin for the Ashkenazi maternal lineages was not statistically justified, given that mitochondrial DNA lineages rise and fall in a random way.

A recent analysis based on the whole genomes, not just mitochondrial DNA, of Jewish communities around the world noted that almost all overlap with non-Jewish populations of the Levant, “consistent with an ancestral Levantine contribution to much of contemporary Jewry.” Dr. Richards said that the finding was compatible with his own, given that the Levantine contribution was not that great.

Another recent study, also based on whole genomes, found that a mixture of European ancestries ranged from 30 percent to 60 percent among Ashkenazi and Sephardi populations, with Northern Italians showing the greatest proximity to Jews of any Europeans.

The authors of this study in Nature Communications, led by Gil Atzmon of the Albert Einstein College of Medicine, noted that there had been mass conversions to Judaism in the early Roman empire, resulting in some 6 million citizens, or 10 percent of the population, practicing Judaism.

Dr. Richards sees this as a possible time and place at which the four European lineages could have entered the Jewish community, becoming very numerous much later as the Ashkenazi population in northern Europe expanded from around 25,000 in 1300 A.D., to more than 8.5 million at the beginning of the 20th century.


 New Low-Cost Technique Isolates Ancient DNA

29 October 2013 09:05

BOSTON, MASSACHUSETTS—A new, low-cost method for purifying ancient human DNA of contaminants acquired in soil was presented by a team from Stanford University at the annual meeting of the American Society of Human Genetics. This method produces samples that have a higher resolution and thus can yield more information than samples produced using other techniques. The approach could also be used to study ancient dog DNA and could be used by forensic scientists. “I think it remains to be seen whether the approach will become a practical method for whole genome sequencing of these difficult but important ancient DNA samples, but I think it is exciting that this is even conceivable,” commented geneticist David Reich of Harvard University.


 45,000-Year-Old Genome of Modern Human Sequenced

LEIPZIG, GERMANY—The complete genome of a very ancient modern human has been sequenced by Svante Pääbo and his team at the Max Plank Institute for Evolutionary Anthropology. “It’s almost twice as old as the next oldest genome that has been sequenced,” Pääbo told NPR. The 45,000-year-old DNA was obtained from cells collected from the center of a femur discovered near the Irtysh River in western Siberia. The analysis shows that the man had long Neanderthal gene sequences, indicating that he’d had Neanderthal ancestors who lived between 50,000 and 60,000 years ago. “They actually mixed with each other and did have children,” Pääbo said. For more on Pääbo's work, see "Neanderthal Genome Decoded."


 DNA Results Reveal Details of Puerto Rican History

Posted by Miguel Vilar on July 25, 2014

Let’s go back 520 years ago to the year 1494 on the island of Vieques, off the southeast coast of Puerto Rico’s mainland.

Tainos, the largest indigenous Caribbean population, were living a life based on the cultivation of root crops and fishing when upon the shores arrived Columbus and his fleet, having crossed the Atlantic Ocean for the second time in as many years. At that point in time everything changed.

What’s written on paper has told us much about what happened next. What’s written in the DNA of today’s Puerto Ricans can tell us some more. 


(Photo by B. Anthony Stewart/National Geographic Creative)

National Geographic’s Genographic Project researches locations where different groups historically intermixed to create a modern day melting pot. Collaborating with 326 individuals from southeastern Puerto Rico and Vieques, the Genographic Project conducted the first genetic testing in the area with the goal to gain more information about their ancient past and learn how their DNA fits into the human family tree. The results, just published in the American Journal of Physical Anthropology, paint a picture of vast historic complexity dating back some 5,000 years, to the first Caribbean peoples.

Our Genographic team learned some key pieces of information that helped us gain more insight into the peopling of the Caribbean. Most surprisingly, we found that roughly 60% of Puerto Ricans carry maternal lineages of Native American origin. Native American ancestry, higher than nearly any other Caribbean island, originated from groups migrating to Puerto Rico from both South and Central America. Analysis of the Y Chromosome DNA found that no Puerto Rican men (0%) carried indigenous paternal lineages, while more than 80% were West Eurasian (or European).

This leads us to conclude that the Y chromosomes (inherited strictly paternally) of Tainos were completely lost in Puerto Rico, whereas the mitochondrial DNA (inherited strictly maternally) survived long and well. This stark difference has been seen in other former colonies (Brazil, Cuba, Jamaica), but the gender dichotomy appears strongest in the Spanish-speaking Americas. A look into the rest of the Puerto Rican genome using the Genographic Project’s custom genotyping tool, the GenoChip, sheds some light on what may have happened during Spanish colonial times to create this ancestral imbalance.

The average Puerto Rican individual carries 12% Native American, 65% West Eurasian (Mediterranean, Northern European and/or Middle Eastern) and 20% Sub-Saharan African DNA. To help explain these frequencies in light of the maternal and paternal differences, I used basic math and inferred that it would take at least three distinct migrations of hundreds of European men each (and practically no European women) to Puerto Rico, followed by intermixing with indigenous women. It also would necessitate the complete decimation of indigenous men (but not women), to account for those numbers. These results are surprising and also shed light into a dark colonial past that, until now, had remained somewhat unclear.

(Map courtesy The Genographic Project)

These types of analyses, not just across the Caribbean or the world, but across a specific population’s DNA, can have strong historical implications and at the same time help paint a new picture of world history. Learn more about how DNA can inform you about your own personal past, and help us uncover some new secrets of world history by joining The Genographic Project.


 Genes and Race: The Distant Footfalls of Evidence

By Ashutosh Jogalekar | May 13, 2014

 A review of Nicholas Wade’s book, “A Troublesome Inheritance: Genes, Race and Human History“.

In this book NYT science writer Nicholas Wade advances two simple premises: firstly, that we should stop looking only toward culture as a determinant of differences between populations and individuals, and secondly, that those who claim that race is only a social construct are ignoring increasingly important findings from modern genetics and science. The guiding thread throughout the book is that “human evolution is recent, copious and regional” and that this has led to the genesis of distinct differences and classifications between human groups. What we do with this evidence should always be up for social debate, but the evidence itself cannot be ignored.

That is basically the gist of the book. It’s worth noting at the outset that at no point does Wade downplay the effects of culture and environment in dictating social, cognitive or behavioral differences – in fact he mentions culture as an important factor at least ten times by my count – but all he is saying is that, based on a variety of scientific studies enabled by the explosive recent growth of genomics and sequencing, we need to now recognize a strong genetic component to these differences.

The book can be roughly divided into three parts. The first part details the many horrific and unseemly uses that the concept of race has been put to by loathsome racists and elitists ranging from Social Darwinists to National Socialists. Wade reminds us that while these perpetrators had a fundamentally misguided, crackpot definition of race, that does not mean race does not exist in a modern incarnation. This part also clearly serves to delineate the difference between a scientific fact and what we as human beings decide to do with it, and it tells us that an idea should not be taboo just because murderous tyrants might have warped its definition and used it to enslave and decimate their fellow humans.

The second part of the book is really the meat of the story and Wade is on relatively firm ground here. He details a variety of studies based on tools like tandem DNA repeats and single nucleotide polymorphisms (SNPs) that point to very distinctive genetic differences between populations dictating both physical and mental traits. Many of the genes responsible for these differences have been subject to selection in the last five thousand years or so, refuting the belief that humans have somehow “stopped evolving” since they settled down into agricultural communities. For me the most striking evidence that something called race is real comes from the fact that when you ask computer algorithms to cluster genes based on differences and similarities in an unbiased manner, these statistical programs consistently settle on the five continental races as genetically distinct groups – Caucasian, East Asian, African, Native American and Australian Aboriginal. Very few people would deny that there are clear genetic underpinnings behind traits like skin color or height among people on different continents, but Wade’s achievement here is to clearly explain how it’s not just one or two genes underlying such traits but a combination of genes – the effects of many of which are not obvious – that distinguish between races. The other point that he drives home is that even minor differences between gene frequencies can lead to significant phenotypic dissimilarities because of additive effects, so boiling down these differences to percentages and then interpreting these numbers can be quite misleading.

Wade also demolishes the beliefs of many leading thinkers who would rather have differences defined almost entirely by culture – these include Stephen Jay Gould who thought that humans evolved very little in the last ten thousand years (as Wade points out, about 14% of the genome has been under active selection since modern humans appeared on the scene), and Richard Lewontin who perpetuated a well-known belief that the dominance of intra as opposed to inter individual differences makes any discussion of race meaningless. As Wade demonstrates through citations of solid research, this belief is simply erroneous since even small differences between populations can translate to large differences in physical, mental and social features depending on what alleles are involved; Lewontin and his followers’ frequent plea that inter-group differences are “only 15%” thus ends up essentially translating to obfuscation through numbers. Jared Diamond’s writings are also carefully scrutinized and criticized; Diamond’s contention that the presence of the very recently evolved gene for malaria resistance can somehow be advanced as a dubious argument for race is at best simplistic and at worst a straw man. The main point is that just because there can be more than one method to define race, or because definitions of race seem to fray at their edges, does not mean that race is non-existent and there is no good way to parse it.

The last part of the book is likely to be regarded as more controversial because it deals mainly with effects of genetics on cognitive, social and personality traits and is much more speculative. However Wade fully realizes this and also believes that “there is nothing wrong with speculation, of course, as long as its premises are made clear”, and this statement could be part of a scientist’s credo. The crux of the matter is to logically ask why genes would also not account for mental and social differences between races if they do account for physical differences. The problem there is that although the hypothesis is valid, the evidence is slim for now. Some of the topics that Wade deals with in this third part are thus admittedly hazy in terms of corroboration. For instance there is ample contemplation about whether a set of behavioral and genetic factors might have made the West progress faster than the East and inculcated its citizens with traits conducive to material success. However Wade also makes it clear that “progressive” does not mean “superior”; what he is rather doing is sifting through the evidence and asking if some of it might account for these more complex differences in social systems. Similarly, while there are pronounced racial differences in IQ, one must recognize the limitations of IQ, but more importantly should recognize that IQ says nothing about whether one human is “better” or “worse” than another; in fact the question is meaningless.

Wade brings a similar approach to exploring genetic influences on cognitive abilities and personality traits; evidently, as he recognizes, the evidence on this topic is just emerging and therefore not definitive. He looks at the effects of genes on attributes as diverse as language, reciprocity and propensity to dole out punishment. This discussion makes it clear that we are just getting started and there are many horizons that will be uncovered in the near future; for instance, tantalizing hints of links between genes for certain enzymes and aggressive or amiable behavior are just emerging. Some of the other paradigms Wade writes about, such as the high intelligence of Ashkenazi Jews, the gene-driven contrast between chimp and human societies and the rise of the West are interesting but have been covered by authors like Steven Pinker, Greg Cochran and Gregory Clark. If I have a criticism of the book it is that in his efforts to cover extensive ground, Wade sometimes gives short shrift to research on interesting topics like oxytocin and hormonal influences. But what he does make clear is that the research opportunities in the field are definitely exciting, and scientists should not have to tiptoe around these topics for political reasons.

Overall I found this book extremely well-researched, thoughtfully written and objectively argued. Wade draws on several sources, including the peer reviewed literature and work by other thinkers and scientists. The many researchers whose work Wade cites makes the writing authoritative; on the other hand, where speculation is warranted or noted he usually explicitly points it out as such. Some of these speculations such as the effects of genetics on the behavior of entire societies are quite far flung but I don’t see any reason why, based on what we do know about the spread of genes among groups, they should be dismissed out of hand. At the very least they serve as reasonable hypotheses to be pondered, thrashed out and tested. Science is about ideas, not answers.

But the real lesson of the book should not be lost on us: A scientific topic cannot be declared off limits or whitewashed because its findings can be socially or politically controversial; as Wade notes, “Whether or not a thesis might be politically incendiary should have no bearing on the estimate of its scientific validity.” He gives nuclear physics as a good analogy; knowledge of the atom can lead to both destruction and advancement, but without this knowledge there will still be destruction. More importantly, one cannot hide the fruits of science; how they are used as instruments of social or political policy is a matter of principle and should be decoupled from the science itself. In fact, knowing the facts provides us with a clear basis for making progressive decisions and gives us a powerful weapon for defeating the nefarious goals of demagogues who would use pseudoscience to support their dubious claims. In that sense, I agree with Wade that even if genetic differences between races become enshrined into scientific fact, it does not mean at all that we will immediately descend into 19th-century racism; our moral compass has already decided the direction of that particular current.

Ultimately Wade’s argument is about the transparency of knowledge. He admonishes some of the critics – especially some liberal academics and the American Anthropological Association – for espousing a “culture only” philosophy that is increasingly at odds with scientific facts and designed mainly for political correctness and a straitjacketed worldview. I don’t think liberal academics are the only ones guilty of this attitude but some of them certainly embrace it. Liberal academics, however, have also always prided themselves on being objective examiners of the scientific truth. Wade rightly says that they should join hands with all of us in bringing that same critical and honest attitude to examining the recent evidence about race and genetics. Whatever it reveals, we can be sure that as human beings we will try our best not to let it harm the cause of our fellow beings. After all we are, all of us, human beings first and scientists second.

A modified version of this review was first published on Amazon.com.

About the Author: Ashutosh (Ash) Jogalekar is a chemist interested in the history and philosophy of science. He considers science to be a seamless and all-encompassing part of the human experience.

The views expressed are those of the author and are not necessarily those of Scientific American.

Scientific American is a trademark of Scientific American, Inc., used with permission

© 2013 Scientific American, a Division of Nature America, Inc.


Home     Return    Top