“You and I, in fact, everyone all over the world, we’re all African under the skin; Brothers and sisters separated by a mere 2,000 generations. Old fashioned concepts of race are not only socially divisive but scientifically wrong. It’s only when we’ve fully taken this on board that we can say with any conviction that the journey our ancestors launched all those years ago is complete.”
The Journey Of Man – A Genetic Odyssey, Spencer Wells The Journey Of Man – A Genetic Odyssey by Spencer Wells is a fascinating take on our civilization. Spencer Wells, popularly known for The Genographic Project, uses genetic markers or inherited mutations to trace the evolution and journey of our ancestors over the last 50,000 years. Today, science has proved that human migration started from Africa about 50,000 years ago, with the first wave traveling to Australia. The tracing of the markers takes place through the Y chromosome found in men, or mitochondrial DNA (mtDNA) passed on by mothers to their children. Markers are typos when genes are not copied precisely to their respective progeny.
Source: The Journey Of Man – A Genetic Odyssey | YouTube
If Africa is the cradle of our civilization, the middle east is the nursery — Spencer Wells
DNA molecules are chains of nucleotides, a pair of double helix nucleotides twisted elegantly. These nucleotide building blocks are of four different kinds- A, T, C, and G. DNA is distributed among the cells. Humans have a thousand million million cells, with almost all cells having a DNA footprint among them. The nucleotide building blocks remain the same for all animals and plants except sequencing of building blocks A, T, C, and G. Every cell in our body contains identical DNA, a pathway in building our body. Forty-six chromosomes or 23 pairs of chromosomes, observable under a microscope as long threads. These chromosomes have genes strung to them in order. 2 An excellent way to look at the human journey is from that of a single cell organism to that of humans with trillions of cells as life emerged from the primordial soup of a single-celled organism. The division of cells that are exact replicas of each other has been one of the most consistent features of our journey through time. Richard Dawkins in his book The Selfish Gene describes DNA as the building blocks of our body with A, T, C, and G as set of instructions for building the body.
# Understanding Markers
Humans have 23 pairs of chromosomes, with one pair of the Y chromosome differentiating between males and females. For females, all 23 pairs of chromosomes are X chromosomes. The Y chromosome shares the guiding light of ancestral history from the paternal side through time as the markers are copied faithfully from generation to generation until there is a mistake in copying the DNAs. These glitches or mutations are passed on over generations; these inherited mutations are called Markers. 1 Since Y chromosomes are found in males; this limits the search of markers to males. Markers help you understand wherein the copying mistake happened over the thousands of years of their ancestors, leading to the person from where the genesis of your lineage started.
Women pass on mitochondrial DNA (mtDNA) to their children, which also records mutations that pass on from generation to generation and help trace ancestral roots on the maternal side. These markers assist in understanding how humans settled across different locations in the world over the last 50,000 years aiding in understanding reasons for distinctive features, traits among the people, etc. The Genographic Project remains one of the most extensive scientific expeditions taken to understand how we are related to hundreds of distinct groups of people called Haplogroups sharing a common ancestral identity. The migration out of Africa took place thousands of years ago at different times due to famine etc. The onset of the Ice age fostered migration to other continents as linkages between continents eased due to connecting ice sheets. The second great migration out of Africa settled in the middle east and from the middle east branched into various countries and continents. Surprisingly, the presence of humans in America was relatively new approximately 13,000 years ago compared to other regions that saw humans settling much earlier. Interestingly, the migration from the middle east did not directly happen to Europe. Instead, it went through Central Asia. Central Asia’s grasslands provided a formidable hunting ground replete with faunas to flourish sustainable living. The use of genetics in deciphering the evolution of humans is by far one of the best discoveries in understanding civilizations giving answers to questions not available through archelogy.
- Journey of Man – A Genetic Odyssey Spencer Wells | YouTube
- The Selfish Gene – Richard Dawkins
- The Journey of Your Past | National Geographic | YouTube
- Genetics | National Geographic | YouTube