A Brief History of Everyone Who Ever Lived by Adam Rutherford
Have you ever fantasized about traveling back through time and seeing the world during a different era? With modern science, that voyage may have just be possible. While time travel hasn’t yet been invented, you can take an exciting tour of history that’s with genetics that is just as riveting.
The way culture developed and passed on, human migration patterns – even such emotionally charged concepts as race and ancestry can now be explored with new scientific techniques. We are finding that as we examine our world more deeply, many of our concepts about society and ourselves start to unravel. Rather than setting us apart from one another, genetics prove just how similar we all are. In this book summary you’ll learn:
- Whether you could be descended from Royalty.
- Why shouldn’t waste money on a genetic test to determine Native American.
- Why our eyes deceive us when it comes to race.
A Brief History of Everyone Who Ever Lived Key Idea #1: Genetic Analysis
Everything seems to be set in stone in the history books. The reality is, a great deal of human history is less than clear. As you travel further back in time, our knowledge becomes hazier.
Even though historians are pretty confident about life and culture in ancient Greece, once you begin to investigate further in the past, putting your finger on the truth becomes more difficult. There is some good news when considering this problem.
With genetic analysis, science is able to look deeper into the past and truly uncover the ancient history of humanity. This technology rests on the discoveries of Gregor Mendel, Francis Crick and James Watson, nineteenth- and twentieth-century scientists who patiently unraveled the mysteries of DNA and the human genome. Thanks to their determination and study, the scientist at the Human Genome Project, following a Herculean effort, deciphered a full set of human DNA in 2000.
This breakthrough allows medical science to analyze the genes of living humans. Perhaps even more valuable, the technique can also extract DNA from archeological samples.
This allows us to study the genes of our ancient ancestors. Called paleogenetics, this new field uses DNA to tell an exciting story about our distant past. While modern humans are known as Homo sapiens or “wise man”, before we evolved, other Homo species existed, such as Homo erectus, Homo heidelbergensis, Homo neanderthalensis, Homo habilis, and Homo ergaster. One of the earliest upright apes was Homo erectus.
The species came into existence on the African continent some 1.9 million years ago before spreading across the globe. Our own species, Homo sapiens, also evolved around 200,000 years ago in the eastern part of the African continent. When Homo sapiens left Africa and entered Eurasia, they would have encountered another species of human, Homo neanderthalensis, commonly known as Neanderthals.
The encounter was a congenial one as it turned out. Our two species interbred – quite often, as a matter of fact. Through genetic analysis, we have discovered that the average European shares around 2.7 percent of DNA with Neanderthals. It may have seemed the species eventually died out, Neanderthals never truly went extinct. It is more accurate to say that they merged with our own species.
A Brief History of Everyone Who Ever Lived Key Idea #2: Changes in cultural practices and the environment leave genetic marks.
Not only can genetic analysis help us understand human evolution better, but it can also clarify the development of culture. This is due to the fact that changes in cultural practices impact our genes and leave lasting clues to their existence. Milk is a great example of one of these clues. While some people drink milk every day with pleasure, lactose intolerance is an issue for a large percentage of adults in the world.
They simply can’t digest the stuff. This begs the question; why is a small group capable of metabolizing dairy? Well, to digest milk mammals need an enzyme called lactase. The ability to produce this is coded into the LCT gene belonging to all humans. For most people, except for those of European descent, this gene becomes inactive after infancy after which a human would not have access to milk.
As a result of a single letter change in the LCT gene, the ability to digest milk as an adult emerged in Europe between the years 5,000 and 10,000 BCE. The emergence of dairy farming among Europeans during this time brought about this change. Genetic analysis can even more specifically pinpoint the changed gene’s emergence somewhere around what’s now Slovakia, Poland or Hungary.
Thanks to different mutations groups in Africa and Asia also developed the ability to digest lactose. Obviously, lactase persistence was advantageous since it introduced up a whole new source of nutrition. It was therefore selected for during human evolution. In addition to culture genetic analysis also allows us to study human migration since genes also change due to environmental factors.
A good example of adaptation to the environment is people of European descent. They possess one standout characteristic: their skin color. It makes sense that the humans who migrated from Africa to Europe 50,000 years ago were dark-skinned since dark skin is an adaptation to sunny weather.
Yet the people who live in Europe now have light skin. Why is this? According to bone analysis, 7,700 years ago humans living in what’s now Sweden had developed genes produced light skin, as well as blonde hair and blue eyes, when acting together.
A Brief History of Everyone Who Ever Lived Key Idea #3: Native American people share similar genes, but DNA analysis can’t confirm tribal heritage.
Columbus was certainly not the first outsider to make the trip when he arrived in the Americas. Viking warriors had landed on American shores five hundred years prior and chose not to bother the people living there. When Columbus landed, it is thought that Native Americans had been calling the continent home for at least 20,000 years.
Genetic analysis can help us understand why they moved to America to begin with, and how their different nations are related to one another. This is the story: Roughly between 29,000 BCE and 14,000 BCE, the entire northern hemisphere was covered with huge glaciers.
This created a frozen bridge to cross the Bering Strait, the space between modern-day Russia and Alaska, which was used by people from Siberian Asia to cross to the American continent Once there, they headed south and spread out across the continent. We can verify this through genetic analysis. It is now known that all Native Americans, both in the north and south of the continent share a common ancestry as they all share versions of genes that trace back to the Inuit people of Greenland.
The Inuit diet is the telltale sign here. Seafood dominated the Inuit diet so adapted versions of fatty-acid-desaturases or FADS genes, which transform the fatty acids in fish into unsaturated fats are found in all the indigenous people of the Americas. While it can tell much about the distant past, DNA analysis cannot reveal to which specific tribe a person belongs.
However, there are companies who claim to do just that. DNA Consultants will sell you a Cherokee test for $99. You can even buy a verification certificate for an extra $25 if your DNA is a confirmed “match”. The American tribes all mixed together, both before and after colonization, and later even intermixed with European settler populations so these tests have no scientific basis. No tribe is marked by unique genetic characteristics. Simply put, there is no such thing as tribal purity.
A Brief History of Everyone Who Ever Lived Key Idea #4: All people descend from royalty.
Have you heard of the ninth-century king and Holy Roman Emperor, Charlemagne? He may just be your ancestor. It’s a fact that everyone has noble blood; it’s just a matter of mathematics. A Yale University statistician, Joseph Chang, discovered everyone’s royal ancestry by analyzing generations with numbers, rather than genes. Chang built a mathematical model to do so.
This model uncovered how far back one has to go to find a common ancestor for all Europeans. The answer; only 600 years. This means all the lines would cross around the time of Richard II of England if you documented the entire family tree of every European alive today going back 600 years. But is this possible? Because each person has two parents, four grandparents, eight great-grandparents, and so on, every person of European descent today should have had billions of different ancestors living a thousand years ago.
But a thousand years ago there weren’t billions of Europeans. This means that every European alive today is a descendant of every single person alive in the ninth century, many of who fill multiple positions in any given family tree. Charlemagne, who fathered 18 children, is the forefather of every person with European ancestry alive today. The same is true of Genghis Khan if you’re Asian. Nefertiti fills the same role if you’re from Africa. There’s an ancient ruler in every person’s family tree across the globe. Still, it’s fortunate for us that not all our ancestors were royalty. Royal families faced serious health risks due to the amount of inbreeding that occurred.
After all, royalty was encouraged marrying royalty – often cousins, to preserve their bloodline. This results in an increased risk of genetic disease for most royal people because they have fewer ancestors than average. Charles II of Spain, born in 1661 is an example of this.
He was born with shriveled genitals and couldn’t have children, a serious genetic disorder exacerbated by close family interbreeding. As might be expected, Charles II had far fewer ancestors than is common and thus less genetic diversity. Charles II had just 82 persons in his family tree over eight generations while a person whose family avoided incest altogether should have 254.
A Brief History of Everyone Who Ever Lived Key Idea #5: Racism may be real, but race is not a scientific category.
Racism: race is not a scientific category. Talking about genetics without getting into the ticklish subject of race is difficult. What can science tell us about his thorny topic? Many attempts to justify racism through genetics have been made in the past.
A former science editor at the New York Times, Nicholas Wende, published a book called A Troublesome Inheritance in 2013. The book claimed that race could be defined genetically and that the DNA of a population accounted for its culture rather than the culture accounting for its DNA. Wende even went so far as to claim that Jews, for example, have genes that are “adapted for success in capitalism.”
It took a while for true genetic analysis to clarify rue genetic analysis that race cannot be described as a scientific category. During the eighteenth and nineteenth centuries, scientists like the German anthropologist Johann Blumenbach made an attempt to put every human into five racial categories: Caucasian, Mongolian, Ethiopian, Malayan and Native American. Stanford scientist Noah Rosenberg published a major study in 2002 using genetic samples from 1,056 people from 52 regions, which disproved this reductive theory. Using a computer to cluster these samples into categories based on their degree of similarity, he asked the computer to divide the samples into five categories. The samples corresponded roughly to accepted racial groupings.
The problem came in when he asked the computer to divide the samples into two, three or four categories and very different “racial” groupings appeared. When he asked the computer for six categories, Rosenberg was surprised to discover the next “race” to appear was the Kalasha, the northern Pakistani tribe with only about 4,000 members.
Rosenberg concluded that dividing people up into groups by using such tiny differences is akin to splitting hairs because there’s so much overlap in the human genome. The computer’s inclusion as a “race” of a small, indistinct group shows just how arbitrary the notion of race is.
Geneticist Richard Lewontin discovered another example of the scientific folly of dividing people by race in 1975. While researching the differences between blood types, he actually found greater genetic differences not between, but within racial groups. Even though there are clear physical differences between races, you’re actually more likely to find genetic differences between two white people than between a black person and a white person. Apparently, our eyes are deceiving us.
A Brief History of Everyone Who Ever Lived Key Idea #6: Deciphering the human genetic code has unraveled several myths.
Where were you on June 26, 2000? It was a historic day, but not likely one to which people paid much attention. To publicly announce that the entire human genome had finally been deciphered, US President Bill Clinton invited the head scientists at the Human Genome Project to the White House. This was groundbreaking for the field of genetics. The Human Genome Project, one of the largest scientific enterprises ever attempted, had successfully deciphered the three billion letters of DNA that compose the human genetic code in just eight years. What was revealed by this work? Three revelations stood out, the first being that humans have fewer genes than was previously thought. Scientists assumed that the human genome would contain something like 100,000 genes or more prior to this decoding.
They were shocked to discover roundworms and bananas have more individual genes than people do, the real number being closer to 20,000. That most of this DNA has little or no apparent function was the second big surprise. Readable genes actually only make up about two percent of the human genome. The rest of the genome material is simply incomprehensible. Known as “junk DNA”, it’s not yet clear whether it’s entirely useless. The project also uncovered a final major insight: the complex nature of the interaction between genes.
For instance, certain types of cancer have long been believed to be caused by specific genes. It’s simply not the case that there is a specific code for a specific outcome. Genome-Wide Association Studies, or GWAS, analyzed the genomes of thousands of individuals with identical medical conditions to prove this.
These studies found that tens to hundreds of genes play a role in any given medical condition rather than identifying single genes as the positive cause of their ailments. It is this intricate interplay that produces cumulative effects, eventually resulting in illness.
A Brief History of Everyone Who Ever Lived Key Idea #7: Genes perform many interactions, and traits acquired during life can be passed onto your offspring.
Have you ever searched Google for the phrase, “scientists discover the gene for…”? If you do, you’ll get a seemingly endless list of results. You might stumble upon an article from 2008 printed in Guardian, entitled, “Scientists discover the gene for cocaine addiction.” Such claims are unscientific nonsense, despite the apparent reputability of the source. But is there so much confusion?
Single genes can be, and often are, misunderstood as determining a specific trait or behavior. This is illustrated in the case of Davis Bradley Waldroup, the man who murdered his wife’s friend and attempted to take his wife’s life as well in Polk County, Tennessee, in 2006.
He had shown murderous intent and faced execution for homicide but he escaped the death sentence. MAO-A gene, which is essential to normal life, was the core of his defense. Waldroup’s DNA showed a variation in this gene has been linked to increased aggression, impulsiveness, and criminal behavior. Whatever the jury decided, the dysfunction in that gene doesn’t relieve Waldroup of guilt. Genetics is a vast field and ever evolving. No single gene can account for such a specific behavior.
While Waldroup’s legal team may have persuaded the jury of his innocence, the world of science is much more skeptical. While they don’t account for specific diseases or behaviors, genes are quite malleable in other ways. Traits acquired during life can, in some cases be passed on to offspring in the next generation.
For example, In the winter of 1944, the population of the western Netherlands starved when the Nazis cut off the food supply. Countless people starved during this Hongerwinter. Those who survived still faced serious medical issues later in life and so, oddly enough, did their children.
Even though they were born years later, the offspring of the survivors went on to develop starvation related medical problems like obesity and diabetes. Epigenetics is the study of the inheritance of traits acquired during life.
This is a scientific oddity. Science has rejected the idea that such a thing is possible since Darwin’s work gained acceptance. Yet epigenetics really doesn’t conflict with evolution by natural selection. Rather, while acquired traits can be passed on for one or two generations, eventually they fade away.
A Brief History of Everyone Who Ever Lived Key Idea #8: Genes perform many interactions, and traits acquired during life can be passed onto your offspring.
Mutants utilize superhuman powers to accomplish all kinds of extraordinary feats in science-fiction movies like X-Men. You may wonder when are we going to evolve to the point where we actually develop such wonderful powers?
As shocking as it may sound, we already have! We have invented airplanes to fly, night-vision goggles that let us see in the dark and all manner of other things that increase our abilities. The truth is, we don’t even need to grow huge wings or odd-looking feline eyes. That doesn’t mean we aren’t evolving physically as well. Humans are still evolving. We will continue to do so as long as we reproduce sexually. With each new baby, the human genome changes and the species as a whole evolves. You might say, from a genetic perspective, we are all simply a means of transition from our parents to our children.
We are also learning that not all genetic changes are positive. In his 2013 research at the University of Washington in Seattle, Josh Akey found many recent changes to human DNA had made the production of proteins less efficient or entirely dysfunctional.
He concluded that while it’s clear that humans are still evolving it is not necessarily natural selection, that should pick advantageous traits that increase our species’ chances of survival, which is driving the change. It’s become had to say what is “natural” when we’ve altered our living conditions so greatly.
Humans have combated disease and aging with ever-increasing success and have created ways to overcome the harsh challenges we face from nature. Because we no longer lose individuals to now curable conditions, the advent of modern medicine has slowed the pace of natural selection. While the pace may have slowed, natural selection is still moving along. Humans die, reproduce and continue to evolve. Until something else changes, Darwin’s theory of evolution is still the best we’ve got.
The key message in this book:
Genetic analysis has opened a new view of the past. Science can now paint sophisticated pictures of human history, based solely on genes and their development. Such techniques offer impartial insights into the complex evolution of humanity and major social issues like race and discrimination.