Let your DNA do the Walking

Forever changed after watching Nat Geo’s, “The Human Family Tree,” I decided to participate in the Genographic Project and not only contribute my DNA to the growing collection but to trace my ancient ancestral origins, and discover the path my ancestors took out of Africa.

The fossil, archaeological and now genetic records have basically confirmed that East Africa is the birthplace of the human species. The oldest fossil of a Homo sapien is dated to 195,000 years in the past, and it’s estimated that our species spent ¾ of our time on Earth in Africa before the great migration began. In what are essentially two migrations out of Africa, Homo sapiens left Africa and ultimately spread across the globe over the last 60,000 years.

I’m very early in my educational process on genetics, so I’ll likely make the mistake of oversimplification, but I’ll give it the old college try. The sex hormones are passed along from parent to offspring essentially unchanged, so the son inherits the father’s Y-Chromosome and the mother’s mtDNA, while the daughter inherits only the mother’s mtDNA. While the male carries the mtDNA of his mother, he cannot pass it along to his offspring.

So as a male, I carry the Y-Chromosome of my father, and his father, and his father and so on until we reach the eldest common ancestor of every man alive today, Scientific Adam. Adam lived approximately 60,000 years ago in Africa as one of many other males, but only his Y-Chromosome lineage still exists today. Mind-boggling I know. I also have the mtDNA my mother passed along to me, which her mother passed along to her, which she got from her mother, and on back through time until we reach Mitochondrial Eve, the woman who all women alive today can claim as their common ancestor. She lived approximately 150,000 years ago in Africa and her mtDNA lineage still survives.

Periodically, small mutations occur in the chromosomes that become markers that can be used to distinguish where a group branched off from the main family tree. By following these changes backwards, geneticists can find the last common ancestor for everyone alive today.

With that very brief overview, I’ll share what my experience in the project has been like as it has altered my view of who I am, where I come from, and how closely related I am to my fellow humans. The kit arrives in a small package that contains two vials and a thin tube with a brush attached at the end, resembling a toothbrush. The kit also has a DVD with instructions, as well as a bonus video on human migration that is a “must see.” The DNA collection process is simply scraping the lining of your cheeks with the brush, and then dropping the brush head into the vial, which has a liquid of some sort in it. The process is repeated after waiting at least 8 hours and then the two vials are shipped off to Nat Geo for processing. Then there’s the waiting.

You can track the progress of your DNA sample on-line using the unique code provided for your sample. Once the results are processed, an interactive map appears along with a narrative description of the story told by your genetic markers. The whole thing can be saved as a PDF document for sharing or printing, etc.

Like many people perhaps, I know where my parents came from, and at least some of my grandparents, but then the trail goes cold. My DNA brought that trail to life.

My paternal ancestors were part of the second great wave of migration out of Africa and followed the expanding grasslands and plentiful game into the Middle East. They then followed the great herds of buffalo, antelope, woolly mammoths and other game through what is now Iran and into Central Asia. Around 30,000 years ago, a descendant of the clan who began making its way into Europe gave rise to a particular genetic marker, M343, which is the defining marker of my DNA. I am a direct descendant of the people who dominated the European expansion, the Cro-Magnon. The Cro-Magnon are responsible for the famous cave paintings found in southern France. Today, 90% of the people in the Basque region of Spain carry my genetic marker.

So, although my father was born in Cuba, he was a first generation Cuban. My grandfather moved to Cuba with his family at the age of 3–the family would find work in the sugar industry–but my grandfather was born in the Canary Islands of Spain. My father knew his grandfather, which would be my great grandfather, who was also from Spain. Additionally, my last name originated in Segovia, Spain in a small town called Villa de Pedraza. So it’s a pretty safe bet that based on the genetic evidence, the limited genealogy that I know and the surname origins, my ancestors hailed from Spain for many, many generations.

So armed with the knowledge of where the men in my family came from, I ordered another kit to track my maternal ancestry. As I waited patiently for the results to come in, I tried not to make any assumptions, but to be honest I assumed a similar path for great, great grandma out of Africa. I couldn’t have been more wrong.

My maternal ancestors left East Africa, but they headed west and didn’t leave the continent. I share the mtDNA with the most frequent and widespread haplogroup in Africa. In fact, the specific group I belong to is almost exclusively in the Senegal area of Africa and surrounding regions. I was a bit befuddled as I read this because my mother, grandmother and great grandmother were all Cuban born women. How’d they get there from Senegal, West Africa?

The history of Cuba shows that the original Cubans–whose ancestors were part of the largest migration in human history–came from the Americas, North, Central and South America. When Columbus discovered Cuba and claimed it for the Spanish, the Spanish enslaved the indigenous peoples, who were ultimately wiped out by disease, including a measles epidemic that wiped out 2/3 of them. The Spanish then needed another way to obtain their laborers.  During the Atlantic Slave Trade, millions of Africans were taken from their land to points around the globe. The very large majority of those taken from West Africa and Senegal specifically ended up in the West Indies, where we find Cuba. So it’s very likely that my maternal ancestors were taken from Senegal sometime between 1650 and 1860 as slaves and brought to the West Indies.

My perspective regarding human life on Earth has been changing for the last few years as I’ve read and studied everything I can handle on evolutionary biology, archaeology, paleontology and genetics. This latest piece of the puzzle has had a dramatic impact as I consider what it all means to me. For tens of thousands of years, generation after generation of my ancestors survived and thrived in what feels like a much smaller world to me now. My grandfathers entered Europe pursing food and shelter, likely encountered Neanderthals there, and settled as the first human beings in what is now Spain.

My grandmothers lived in West Africa until the recent past when they were likely yanked from their homeland and sold at markets in the West Indies like property. But they persevered, had daughters who carried their mtDNA and ultimately brought my mother into the world.

​I salute you Scientific Adam and Mitochondrial Eve. Your DNA runs through my blood, and everyone else living today.


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