I am related to every person living in the world today. Incredible as it may seem in this agonising age of constant discord, so are you and the remainder of our planet’s entire 7.7 billion people.
Decades ago, scientists began unravelling our most ancient maternal and paternal heritage, down to our earliest shared ancestors who existed in Africa roughly between 150,000 and 200,000 years ago. Confirmation of my own “Out of Africa” numbered model, came in a summarised genetic analysis, indicating that while I am considered 100 percent “Broadly South Asian,” indisputably, I descend from this long line of women traced back to eastern Africa over 150,000 years ago.
Fascinated and excited, I slowly scrolled through the several sections of my personalised ancestry and health report released on Emancipation Day, August 1 last, thinking of how appropriate a date, for rocking the cradle and finally learning some of the secrets of my distinct DNA, or deoxyribonucleic acid, derived by a leading private genomic company from a single saliva sample. DNA is the hereditary material composed of two chemical chains that coil around each other to form the famous double helix of life, carrying unique genetic instructions that makes each of us who we are.
Most of an individual’s DNA is repeated in the nucleus of every cell, but a minute amount lingers in the power plant or mitochondria which generate about 90 per cent of the body’s energy from the food we eat and the oxygen we breathe. Termed mitochondrial DNA or mtDNA, it has been indelibly passed down through an unbroken line of millions of mothers in many millennia, dating all the way back to our matrilineal most recent common ancestor (MRCA), the universal mother of us all.
Named Mitochondrial Eve, she is still here inside each minute cell, forever reminding us of the sheer scientific evidence of our African ancestry, with each fresh genome that is sequenced and each report that is sent out. As caring mothers do, whether we like it or not, and whether we accept it or not, she stands with her meaningful message, probably grieving from the grave, far above the never-ending circles of political and racial division, that are widening in Guyana the permanently polarised country where I was born, the neighbouring crime-cursed twin-islands where I currently live, and across far too many colour-obsessed areas of the world.
Particularly prophetic are the well-loved words of the now ailing Trinidadian calypsonian Black Stalin, who pronounced in 1979, way before no confidence motions, coalitions and collisions, and with all the regional emphasis of the stinging double negative: “Caricom is wasting time, the whole Caribbean gone blind, If we don’t know from where we coming, then we can’t plan where we going” for “a man who don’t know his history can’t form no unity.” He questioned, “How could a man who don’t know his roots form his own ideology?” Black Stalin won the country’s coveted Road March with his “Caribbean Man” classic, concluding with brilliant insight, “That there’s one race, From the same place, That make the same trip, On the same ship.”
With the great technological advances we enjoy, geneticists have learnt that Black Stalin is right, as our ancestors ventured out of Africa and branched off in diverse groups that criss-crossed the globe over tens of thousands of years. Some of their migrations can be traced through haplogroups or families of lineages that descend from a common ancestor, like Mitochondrial Eve, unfortunately given a Biblical misnomer that has therefore proved somewhat confusing for the public. She was not the first human, but every other female lineage that we know of failed to pass on their mtDNA. Within hers and the male equivalent line christened Y-chromosomal Adam who lived around the same evolutionary time, give or take a few thousands of years, lie the bits of genetic material and all the variation they have passed down to the vast expanse of humanity.
The company I used, explained that each generation, mothers pass down these copies of mtDNA to their children, but while most of the genome exists in 23 pairs of chromosomes that exchange pieces between generations in a process called recombination, mtDNA is transmitted unshuffled. Due to this unusual pattern of inheritance, mtDNA contains rich information about maternal lineages.
A small number of DNA changes, called mutations, generally occur from one generation to the next. Since mtDNA does not recombine between generations, these mutations accumulate in patterns that uniquely mark individual lineages. Scientists can compare the sequence differences that result by constructing a tree. This tree shows how maternal lineages relate to one another, including the MRCA observation, the company 23andMe added.
Y-chromosomal Adam is the patrilineal most recent common ancestor (MRCA) of all men living now. The term reflects the Y 23rd chromosome which produce human males and is directly derived from this remote African ancestor that is fecund father to the world, handing down his genes to his countless sons through the ages. Different populations have drifted apart, forming the various ethnic groups we see today, but carrying the unmistakable genetic proof of the species’ earliest mom and dad. In 2014, experts announced that a man who fished in the cold waters along the coast of southern Africa and died 2300 years ago, is the closest link yet known to humanity’s common female mother, Mitochondrial Eve. About 50 years old, identified as a member of a previously unknown branch on the human family tree, he is the first ancient human from sub-Saharan Africa, the cradle of humanity, to have his DNA sequenced.
The truth remains uncomfortable for many locked in ignorance, but none of us today are pure racially, we are all mixtures. For example, I carry Neanderthal DNA in the form of 201 variants, out of nearly 3000 tested by the American company 23andMe.
The story of my paternal line is short because I am female and lack the Y chromosome. Yet, I am delighted that geneticists have worked out that I descend from a long line of men led by Y-chromosomal Adam. who can be traced back to eastern Africa over 275,000 years ago. My own father is dead, all his brothers and my paternal grandfather are gone, and only the younger of my two brothers remains, so I have asked him to help me determine our patrilineal history by taking the test.
For now, I am engrossed in the findings including that my maternal line began long ago with Mitochondrial Eve who was one of perhaps thousands of women alive at the time, but only the multiple branches of her original haplogroup “L”survive today. One of these, “L3” spread out in the continent 65,000 years ago, followed by subsequent migrations by “N” about 6000 years later and then “R.” The firm identifies haplogroups by deciding which branches of the mtDNA tree correspond to my DNA, peeking into geographic root. Maternal haplogroups are named with sequences of letters and numbers that reflect the structure of the tree and how the branches relate to each another.
My maternal line stems from “R5,” one of the earliest to arise from haplogroup “R” in India. “R5” goes back to a woman who likely lived among the inhabitants of present-day southern India just over 35,000 years ago. Later, the haplogroup spread north, but it never expanded beyond the Indian subcontinent.
My special maternal haplogroup “R5a2” belongs to a woman who lived approximately 16,500 years or 660 generations ago. As researchers and citizen scientists discover more, new details may be added to the story. I will be waiting.
ID sings Black Stalin’s “Caribbean Man” and laughs that she has no Neanderthal variants associated with having straighter hair, a reduced tendency to sneeze after eating dark chocolate, less back hair and height.
