Our Mother, Our shared legacy
Imagine a journey back in time to the dawn of humanity. You follow the footsteps of your ancestors, travelling across vast continents and treacherous seas. Along the way, you witness the birth of new cultures and the rise and fall of civilizations. Your journey finally ends at the doorstep of Mitochondrial Eve, the matrilineal most recent common ancestor of all living humans. She is the shared mother of us all, a symbol of our interconnectedness and our shared history.
In this blog post, we will explore the fascinating story of Mitochondrial Eve. We will delve into the science behind this concept, its implications for our understanding of human evolution, and some common misconceptions.

What is the significance of Mitochondrial Eve for our understanding of human ancestry?
Mitochondrial Eve is a term that scientists use to describe the woman who is the most recent common ancestor of all humans alive today, in terms of matrilineal descent. This means that she is the most recent woman from whom all living humans descend in an unbroken line purely through their mothers. But how do we know about her? It’s all thanks to something called mitochondrial DNA (mtDNA). Unlike most of our DNA, which we inherit from both parents, mtDNA is passed down only from mother to child.
Mitochondria are tiny organelles that live inside our cells. They are often called the "powerhouses of the cell" because they produce most of the energy our cells need to function. Mitochondria also have their own DNA, known as mitochondrial DNA (mtDNA). Unlike nuclear DNA, which is passed down from both parents, mtDNA is inherited only from the mother. This means that all of the mtDNA in your cells is identical to the mtDNA in your mother's cells, and her mtDNA is identical to her mother's mtDNA, and so on.
Scientists can trace this unbroken line of inheritance back to a single woman who lived around 200,000 years ago in Africa. This woman is known as Mitochondrial Eve. It is important to note that Mitochondrial Eve was not the only woman alive at her time, nor was she the first human woman. However, she is the woman to whom all living humans today can trace their mtDNA. By studying variations in mtDNA, scientists can learn about our human family tree and how we are all connected.
Scientists can use mtDNA to track the migration of human populations around the world and help us to understand the evolution of diseases. For example, some diseases are caused by mutations in mtDNA. By studying these mutations, scientists can learn about the history of the disease and how it has spread through the human population.
The concept of Mitochondrial Eve was developed in the late 1970s by a team of scientists led by Allan Wilson. Their research has been fundamental in our understanding of human evolution and migration patterns. Mitochondrial Eve is a powerful tool for understanding human evolution because it gives us a direct line of descent from our ancestors. By studying mtDNA, scientists can learn about the genetic diversity of human populations, how populations have migrated and interbred over time, and how these events have shaped our evolution.

Where is the homeland of Mitochondrial Eve?
A Cradle of Civilization
Research suggests that the homeland of Mitochondrial Eve was in Africa's Kalahari Desert, specifically in a region known as the Makgadikgadi paleowetland. This vast wetland was roughly twice the area of Lake Victoria, Africa's largest lake today. Around 200,000 years ago, the Makgadikgadi was a verdant oasis, with lush forests and grasslands where our earliest maternal ancestors lived for tens of thousands of years.
Earth's climate changes and shifts in rainfall patterns have significantly impacted the Makgadikgadi region over time. As the climate changed, shifts in rainfall opened up fertile new paths through the desert, allowing our distant relatives to explore new territories beyond their initial homeland. This migration marked a significant event in human history, as it was the beginning of our ancestors' journey out of Africa and into other parts of the world.
By studying the genomes of indigenous Africans living in the southern part of the continent today, researchers have pieced together a history of one of the oldest DNA lineages on Earth: a collection of genes called L0. This lineage is passed down maternally through mitochondria and has survived remarkably unchanged in some populations for hundreds of thousands of years. By tracking where and when the L0 lineage first split into slightly different sublineages still seen in some indigenous African people today, researchers believe they have pinpointed precisely where the first carriers of L0 lived and thrived for thousands of years: the Makgadikgadi paleowetland.
Despite these migrations and changes over time, the lineage of Mitochondrial Eve remains remarkably preserved in the indigenous populations of southern Africa today.

What are some common misconceptions about Mitochondrial Eve?
There are several common misconceptions about Mitochondrial Eve. Here are a few of the most common:
Mitochondrial Eve was the first woman or the only woman alive at her time. This is not true. Mitochondrial Eve is simply the most recent woman from whom all living humans descend in an unbroken line through their mothers. There were many other women alive at the same time as Mitochondrial Eve, but their maternal lineages did not survive to the present day.
The position of Mitochondrial Eve is fixed in time. This is also not true. As lineages die out, the position of mt-MRCA (Mitochondrial Most Recent Common Ancestor) moves forward in time.
Mitochondrial Eve was the first member of a "new species." This is a misconception that arises from a misunderstanding of the concept of species. Species are not defined by mitochondrial DNA alone, and there is no evidence to suggest that Mitochondrial Eve was the first member of a new species.
Mitochondrial Eve is the Most Recent Common Ancestor (MRCA) of all humans. This is not true. The MRCA is the most recent ancestor from whom all living humans descend, both through male and female lines. Mitochondrial Eve is only the most recent matrilineal ancestor, meaning that she is the most recent ancestor from whom all living humans descend through female lines only.
Mitochondrial Eve lived 6,000 years ago. This is a misconception that is often promoted by creationists. However, there is no scientific evidence to support this claim. The age of Mitochondrial Eve is estimated to be around 200,000 years old.

Conclusion
The concept of Mitochondrial Eve is a powerful reminder that we are all connected. We all share a common ancestor, and we all carry a piece of her DNA within us. Mitochondrial Eve's story is a testament to the resilience and continuity of human life. It is a story that connects us all, regardless of our backgrounds or origins.
As we continue to learn more about human genetics and ancestry, we gain a deeper understanding of our shared humanity and our place in the world. We encourage you to delve deeper into this fascinating topic. There is still much to learn, but each new discovery brings us closer to understanding who we are and where we come from.
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References:
Stringer, Chris, et al. "A modern human origin in eastern Africa around 200,000 years ago." Nature 431.7007 (2004): 517-521.
Sykes, Brian. The Seven Daughters of Eve. Bantam Press, 2001.
PBS NewsHour, 2019. Cradle of modern human life found in Botswana, maybe [online]. Available at:https://www.pbs.org/newshour/science/cradle-of-modern-human-life-found-in-botswana-maybe
Live Science, 2019. Mitochondrial Eve: Mother of all humans lived 200,000 years ago [online]. Available at: https://www.livescience.com/mitochondrial-eve-first-human-homeland.html
Britannica. Kalahari Desert - Climate [online]. Available at: https://www.britannica.com/place/Kalahari-Desert/Climate
PBS Eons, 2019. The Two People We’re All Related To [video online]. Available at: http://www.youtube.com/watch?v=YNQPQkV3nhw
The African Scientist, 2022. Mitochondrial Eve | The Mother of Humanity [video online]. Available at: http://www.youtube.com/watch?v=v7kjzARgIdY
Yathish Dhavala, 2019. Mother of Humanity (Mitochondrial Eve) [video online]. Available at: http://www.youtube.com/watch?v=rx_oUd-05ys
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