Are we all related?

Here you are, standing at the center of it all.

And surrounding you, like an immense pyramid stretching into the depths of the past, rests your lineage, delicately balanced atop your very being.

Now, if we delve into the question of how many ancestors you possess, let's start with the basics. You have two parents, from whom you descend.

Expanding further, you find yourself with four grandparents who contributed to your existence.

Pushing back yet another layer, there are eight great-grandparents who play a part in your ancestral tapestry.

And if we trace this line of direct ancestors back four generations, we arrive at a total of 30 individuals.

Now, let's embark on a thought experiment. Imagine we continue to double the number of ancestors at each step as we progress along this path. Merely 40 generations into the past, we would encounter an astonishing trillion ancestors, all coexisting within the same timeframe.

The sheer magnitude of this number is mind-boggling. It surpasses not only the count of individuals who have ever lived but even exceeds the number of stars adorning our majestic Milky Way galaxy.

Considering that our species emerged around 200,000 years ago, we estimate approximately 7 or 8 thousand generations of humans leading up to the present moment, to you.

So, where might your seemingly absent ancestors be hiding? The answer lies in the intricate web of human connections throughout history. It becomes evident that there must have been some intermingling and interbreeding within our ancestral lines.

Thus, as you stand here today, you represent the culmination of a vast and interconnected tapestry of countless lives, a testament to the diverse paths and shared heritage that have shaped you. Let's explore the intricacies of human lineage, where family trees naturally diverge in fascinating ways. Before the era of Tinder and modern transportation, people's choices for potential partners were often limited to the scope of their immediate surroundings.

Intriguingly, even prominent figures like Charles Darwin and Albert Einstein married their first cousins, indicating a historical prevalence of unions between close relatives. However, it's important to note that we're not referring to the extreme cases of banjo-playing, King-of-Spain, or Cersei-Jaime kind of inbreeding.

As we delve into the complexities of human history, accounting for factors such as migration patterns, societal structures, life expectancy, trade networks, geography, and even the influence of figures like Genghis Khan, we uncover an intriguing revelation. Every single person alive today shares a common ancestor in their family tree who lived a mere 3,000 years ago.

Yes, it's true. The next time you engage in a heated argument with a stranger on the internet, remember that you both share a common great-great-great-great-great (and so on) grandfather or grandmother. However, the identity of this common ancestor remains a mystery. They didn't leave behind fossils, artifacts, or any written notes about their existence. Although, it would have been quite a thoughtful gesture if they had written birthday cards for each of their 7.4 billion great-great-great-great (and so on) grandchildren.

Nevertheless, the record of our ancestors resides within us, carried in the very fabric of our genes. As DNA is replicated and passed down through generations, occasional errors occur, akin to a slightly blurred copy of a copy. These genetic mutations, although often inconsequential to the functioning of our biological systems, accumulate steadily over time. Scientists interpret these changes as a molecular clock, allowing them to estimate the passage of time and determine the degree of relatedness between individuals based on shared genetic markers.

So, within our genes lie the secrets of our ancestral heritage, unveiling the intricate web of connections that bind us together and illuminate our shared human story. Although humans may appear remarkably diverse, at the DNA level, we share a striking similarity. In fact, groups of chimpanzees living in close proximity in Central Africa exhibit more genetic variation than the entire human population combined. This genetic likeness hints at the relative youth of our species in the grand scheme of things and suggests that, at one point, our population may have been as small as 10,000 individuals. To put this into perspective, it's only about a third of the average crowd size at a Bruce Springsteen concert. Apologies, Boss.

In the present day, any two humans differ from each other by approximately 1 out of every 1000 DNA base pairs. Considering the vast size of our genome, this still amounts to millions of single-letter differences known as single nucleotide polymorphisms (SNPs). These SNPs tend to occur in combinations, forming distinctive patterns associated with specific geographic locations.

DNA ancestry testing companies examine thousands of these single-letter changes in your genome to create a unique genetic signature for your individual variation. They compare your signature to thousands of reference individuals from various parts of the world, utilizing sophisticated algorithms to determine the geographic origins of specific portions of your genome. Personally, my genetic results closely align with this pattern. Both sides of my family hail from Northern Europe and Scandinavia, which explains my last name, my tall stature, my lack of tanning ability, and also why I possess a higher proportion of Neanderthal DNA than two-thirds of the population.

Curious about the presence of Neanderthal DNA in my genetic makeup? If so, I recommend watching our previous video, where we delve into this topic. While I didn't encounter any surprising revelations, many individuals discover previously unknown aspects of their ancestry through such investigations. Our origins are not always evident based on external appearances, but DNA provides an unwavering truth.

Previously, using mathematical calculations, we identified an ancestor who is relatively recent in terms of our shared heritage. However, the genetic influence of that individual has undergone significant reshuffling and is no longer discernible in our DNA today. Is there someone whose genes have been passed down, unchanged, to the present day? Is there a lasting fingerprint from the mother of all living humans?

Indeed, there is. You possess a 47th chromosome residing within the mitochondria, famously known as the POWERHOUSE OF THE CELL! Yes, we had to mention that again. Mitochondria were once free-swimming organisms with their own genetic material. Unlike your other 46 chromosomes, there is no shuffling of genes when mitochondria are passed from one generation to the next. Moreover, all of your mitochondria come exclusively from your mother's egg, not your father's sperm. They trace an unbroken lineage of female ancestors stretching back through every generation of your family tree.

By studying the accumulated changes in mitochondrial DNA over thousands of years, scientists have determined that the most ancient human mitochondrial DNA originates from Africa, the birthplace of our species. In fact, it can be traced back to a single woman who lived approximately 150,000 years ago. While other Homo sapiens females existed alongside her, it is only her lineage that survives to this day, with all other lineages becoming extinct. She is known as Mitochondrial Eve, and every single one of us can trace our ancestry back to her. In the truest sense, we are indeed a global family, connected by our shared genetic heritage. Even if we're distant relatives, perhaps even hundredth cousins, our shared ancestry encompasses not only the branches that stretch into the past but also a tree that extends into the future. In the present day, we possess more power than ever before to shape that future, even down to the intricacies of our genetic makeup.

So, what might lie ahead for our species? That is a question we will explore in the next installment. It is a fascinating journey that invites us to stay curious and delve into the possibilities that await us.

This video is part of a special series dedicated to unraveling the story of our species. We delve into where we came from, how we are all interconnected, and the unique circumstances that have led us to be the sole surviving humans today. If you haven't already, I encourage you to watch parts 1 and 2 of the series, which trace the fossils embedded within our family tree and provide insights into why we stand alone as humans.

The adventure continues, and the mysteries of our past and future await.