Wouldn’t it be amazing to jump in a time machine and travel through the past? Just to see what it was like. What people ate and where they went – it would be fun, wouldn’t it? Well, thanks to science, there is a way you can do just this. Genetics now provides a way to trace a path through history finding out more information not just about heritage but also about culture, migration and diet.
This new insight into the past is just as exciting as it is informative. The best part is, it clearly shows that we all have more in common than we think.
In this book summary readers will discover:
- The three things the human genome told us when deciphered
- How genes are passed
- Where we come from
- Everyone has descended from royalty
- Human evolution is ongoing
Key lesson one: The three things the human genome told us when deciphered
When the human genome was first deciphered in 2000. It was and still remains an amazing achievement by all those involved. It took them eight years of hard work but they eventually gained the total human genetic code. This feat was done in order to better understand human genetics, origins and solutions to genetic diseases. What they found, however, were three things that would change genetic research from that moment on.
Firstly, contrary to popular belief at the time, humans have surprisingly few genes. It was always assumed that the human genome would have more than 100 000 genes. After all, we are quite complex organisms. However, when the human genome was finally decoded, it was found that humans have approximately 20 000 genes.
Secondly, most of the DNA found was deemed to be useless. That is, they had little or no function and was therefore named junk DNA. Junk DNA accounts for 98 per cent of the human genome. This means that the human body requires just 2 per cent of the DNA it carries to function.
Lastly, it was discovered that genes share complex interactions with each other. This was evident when scientists analyzed people with the same medical issues. There were no single genes that could be identified as the cause of their conditions. They instead revealed hundreds of genes that are involved in the expression of an illness.
This was just the beginning of the research to follow. It was a major step in highlighting the complexity of the human genome and it allowed scientists to move forward with the confidence to gain more answers.
Key lesson two: How genes are passed
Genetics don’t only tell us how we have evolved, it can also give great insight into culture. Believe it or not, changes in cultural practices have an effect on our genes and can thus be traced. One of the best examples to consider is that of milk. As strange as it may sound, lactose intolerance was the norm for most adults around the world. We need an enzyme called lactase to digest milk and it is present on the LCT gene which all humans possess. This gene, however, usually goes inactive after infancy. This was a common occurrence to all adults who did not come of European descent. Europeans were able to digest milk in adulthood due to a slight change in the LCT gene that was brought about by dairy farming.
This cultural change has been tracked specifically to somewhere around Slovakia, Hungary or Poland. In other parts of the world, the ability to digest milk also came about to different mutations and since it proved advantageous, it was naturally selected. Thus exhibiting how a change in culture like dairy farming can have an impact on our genes.
It’s not only cultural changes, the environment also has a role in gene expression. Skin colour is one such adaptation. Our ancestors from Africa were dark-skinned as a result of the sunny weather experienced. Lighter skin colour only emerged about 7700 years ago in Sweden.
Even more evidence comes from the fact that we can acquire traits in our lifetime that will be passed on to our offspring. There’s a whole area of research called epigenetics dedicated to researching these traits. At first, scientists rejected epigenetics as being a possibility. It is actually rare but quite possible. A good example came from the people of the western Netherlands who were cut off from their food supply by the Nazis in 1944. It was referred to as the Hongerwinter and resulted in many deaths. Those who survived suffered from many ailments later on but it didn’t stop with them. Their children, who were born years later, also developed ailments such as diabetes and obesity.
Key lesson three: Where we come from
Historians can only tell us so much about the past before things become unclear. Then they begin theorising. Genetic analysis, however, allows scientists to gain the truth about history. They are able to compare samples of DNA taken from our ancient ancestors with those of humans today. This is called paleogenetics and has opened the doors to new discoveries about our origins.
For example, scientists have been able to trace the origin of Homo Sapiens and the migration patterns of earlier Homo species. One of the earliest apes, Homo erectus, came into being some 1.9 million years ago in Africa. They then proceeded to spread all around the world. Homo sapiens also originated in the eastern parts of Africa around 200 000 years ago. When Homo sapiens left Africa for Eurasia, they met another Homo species, Homo neanderthalensis. And while the neanderthals eventually died out, they didn’t necessarily become extinct. This is evident in the fact that the genes of Europeans today share 2.7 per cent of them with neanderthals. This means that they most likely merged with Homo sapiens as opposed to going extinct.
Genetic analysis has also shed some light on Native Americans and when they arrived on the continent. Sometime in the past, due to the extreme cold, the northern hemisphere was covered with glaciers. This allowed people from Siberian Asia to cross the Bering Strait into Alaska. It was from here they were able to spread further south and across the American continent. All Native Americans share genes that can be traced back to the Inuits of Greenland. This implies that they all share a common ancestry. These genes that are shared are related to the Inuit diet. Their diet consists mainly of seafood which led to them having uniques versions of fatty acid desaturases or FADS genes.
Key lesson four: Everyone has descended from royalty
Guess what? You have royal blood! Thanks to Joseph Chang, we now know that if you go back 600 years you are likely to find a noble ancestor. In fact, if every European were to put together their family tree going back 600 years all lines would cross when Richard II was king of England. There’s a simple reason for this. Back then the human population was not as huge as it is now. Each person in the ninth century is probably related to multiple Europeans today. In fact, Charlemagne, the Holy Roman Emperor in the ninth century had 18 children making every person of European ancestry his descendant.
This is not only true of Europeans. Similar relations have been found between Asians and Genghis Khan, and Africans and Nefertiti. Thus, everyone alive today has someone royal in their ancestry. As much as this is an amazing fact to discover, we also have to be grateful that all our ancestors were not royal. Inbreeding was common in royal families in an attempt to keep the bloodline pure. However, as we all know, this had some serious consequences. Genetic diseases were prevalent in royal families. The worse case was seen in Charles II of Spain, the last of the Habsburgs. In normal families, over eight generations, there should be approximately 254 ancestors – Charles II had 82. His genes revealed that his parents were so closely genetically related it was even more so than siblings. His resulting condition was so severe, he had an underbite that left his mouth open constantly, was intellectually challenged and sterile.
Key lesson five: Human evolution is ongoing
Every time a human reproduces they ensure that evolution will continue. How? Well, each new offspring brings with it a slight change in the human genome. Genetically speaking, we are but transitional, being the genetic bridge between our parents and children. As poetic as that may sound, changes in genes, however, are not as quick or beneficial as they have been historically as natural selection has been somewhat hindered by modern living.
In essence, natural selection should identify advantageous traits that can be passed on to ensure our survival. However, research has shown that recent changes in DNA are actually not beneficial at all and has made the protein production less efficient. The simple truth is that natural selection cannot occur when we have altered the nature that surrounds us. Before we evolved when faced with a challenge produced by nature but now, there are other ways to overcome it. Modern medicine enables us to live longer and cure diseases that would have usually triggered some sort of genetic change over time. Ageing is also slowed due to lifestyle choices and increased care.
This does not mean we have stopped evolution from occurring. It just means that the rate at which it occurs has slowed down dramatically.
The key takeaway from A Brief History of Everyone Who Ever Lived is:
Genetic analysis has changed the way we consider our past. No longer is there guesswork and theories needed. DNA now gives us the truth of what occurred, when and where. This is a huge step for research and we can now fully understand human evolution from a number of perspectives. There are a number of factors that have contributed to changes in gene expression over the year and they have each provided an interesting implication in our lives. As we continue to go forward and pursue genetic research, the more we learn of ourselves, our ancestors and our potential.
How can I implement the lessons learned in A Brief History of Everyone Who Ever Lived:
Racism is a real problem in society today and whilst skin colour may be the reason for discrimination, genetics tell a different story. Our skin color is only a result of our ancestry and environment. It does one well to remember that we all have originated from a dark skinned ancestor from Africa. Furthermore, genetics has revealed that there are more genetic differences between people of the same race that from different races. We are all alot more alike that we could ever imagine.
