Where do I come from originally

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This family history has taken us back a thousand years but there is another deeper approach. Our DNA can trace us back to a series of major migrations out of Africa commencing around 400,000 years ago. My genes had been busy evolving deep within my antecedents and culminated in me – you may ask was it worth all that effort? I provided my DNA and $99 to find out more from the Genographic Project (via National Geographic).

One half of my twenty-three chromosomes came from my father and the other half from my mother. These are said by nativist psychologists to predetermine or predispose certain of our features and characteristics, including attributes evident at birth such as eye, hair and skin colour. Not that ‘at birth’ was very informative for me as I was blonde and blue eyed for my first few years, both turning brown later. The hair of course settled for grey later still.

Me

Our genes also determine our vulnerability to events such as hair loss, certain diseases and our life expectancy – not that this stops the pharmaceutical companies endeavouring to tinker with these. Nativists ponder how far this genetic inheritance extends in shaping our intellect and mental capacities, perhaps colouring our opinions, attitudes and approaches to life. Rather unsatisfactorily they appear to conclude simplistically that the earlier a trait appears during our development then the more likely it is to have been from our genes.

Of course our attributes are also heavily shaped and determined by our nurturing. Certainly our first three years is generated by our parents. They also play a significant role through the twelve to fifteen years while most of us live at home battling through our education.

So parenting passes on the genetic markers deep within us and then plays a major role in our nurturing. This fifteen years of the 70-year promised lifespan equates to over 20% of our life, making our parents’ role highly significant.

Neanderthal tendencies?

The Genographic Project’s first test was to see how much Neanderthal I had in my genes.

Current theories suggest that we derive from Homo heidelbergensis, a species first discovered in 1907 near Heidelberg, Germany – hence the name. This species emerged in Africa and between 400,000 to 300,000 years ago a group migrated north-west out of the continent, at some later stage splitting into two groups. Those who migrated west into Europe became known as Neanderthals and those who turned eastward evolved into Denisovans. They are termed Neanderthal merely because their first remains were discovered in the Neander valley, near Dusseldorf in Germany, and Denisovan they were first discoved in the Denisova cave in Siberia (found in the 1970s but understood in 2008). Both groups have been long extinct.

The stay-at-home Africans, Homo heidelbergensis, later evolved into a new species, Homo sapiens sapiens. Of slender build and bipedal, with an average brain size of 1350cc, homo sapiens sapiens had a rising forehead, very small eyebrow-ridges and a prominent chin – essentially much the same as we are today – and this species represents the only hominid existing today – us!

A number of haplotype mutations have been shown to have taken place within Africa before the next major northward migration. The ice in northern Europe had begun to melt and recede. As Africa became warmer and moister, areas of the Sahara became both passable and habitable. The animals habitually hunted by our ancestors roamed further north and we followed them. These hunters represented the first modern humans to leave Africa. All of us found outside Africa today derive from these groups that left the continent between 70,000 and 60,000 years ago.

This next wave of modern humans would of course have encountered those earlier migrants, the Neanderthals and Denisovans, on their travels. Neanderthals became extinct between 41,000 and 39,000 years ago. Around the same time as these earlier hominids were becoming extinct some 40,000 years ago there was another climate change. Drought turned North Africa and the Middle East back into desert, effectively ‘slamming the door’ behind those modern northern migrants for 20,000 years. So my ancestors, maternal and paternal, had set off and could not return to Africa, thus promoting a continuing migration north, east and west.

There is evidence there was ancestral interbreeding with the Neanderthals and Denisovans before their extinction. Most Europeans and Asians carry a memento of these (much maligned!) hominins; between 1% and 4% of their DNA is Neanderthal.

I’m not sure I should feel joy but I should mention my contentment that I prove to be down at the bottom end of that scale, my DNA being just 1.2% Neanderthal – and I am also low compared with the Genographic Project’s current average of 2.1%. Perhaps it was just that my antecedents were late-arrivals or not very good at meeting the neighbours?

My haplogroups have been tested and suggest I am R-Z8 (paternal) and K2A (maternal) – more below. Of all those (some 740,000+) who have submitted material to the Genographic Project I appear to be relatively unusual in that my paternal RZ-8 haplogroup is shared with only 2.8% (1 in 36) of the participants and my maternal K2A with just 0.3% (1 in 333). Nice to feel special, but let’s look a little deeper.

The science bit

You can safely skip this if it doesn’t interest you.

Our personal DNA is created by a combination of two half-sets made up from our parents’ DNA. These half-sets are called haplotypes. We combine one inherited haplotype from our father and one from our mother.

Our chromosomes, Source: flikr.com

The Y-chromosome is passed on unchanged from father to son, and the mitochondrial DNA (mtDNA) is passed on by mothers to each child, though only female offspring pass it on.

Investigating these Y-chromosomes reveals that my first traceable ancestor, and yours, goes back a very long way. Between 300,000 and 150,000 years ago the common paternal ancestor of all of today’s men was born in Africa. Of course he was not the only male of his time, it is merely that only his lineage and his Y-chromosome survived to be passed down to all humans today – the first alpha-male. Of course the popular press promptly heralded him as the Y-chromosome Adam. This Adam was defined as bearing the A00 haplotype – a version only found only in African populations. Yes, we are all descended from Africans!

In the meantime female evolution can be tracked through the mitochondria, located in a circular molecule with its own genome sequence of thirty-seven genes (not the Y-chromosome’s 46). Down the years mitochondria have mutated and tracking the major haplotypes allows geneticists to categorise. This mitochondria investigation has shown that all current living human beings derive from an individual woman, inevitably referred to as the Mitochondrial Eve. She lived around 180,000 years ago in East Africa and handed on the L haplotype which is shared by every woman in the world today.

Migrations

By tracking the mutations present in my DNA the Genographic Project can suggest something of the route that my antecedents must have taken. Once again the surprise is quite how far afield we Dentons wandered.

My paternal migration route can be established by identifying where certain mutations first occurred. Modern humans emerged from the Rift Valley. Around 100,000 years ago and still in East Africa my first mutated marker occurs – P305. This is none too surprising as 99.99% of all of today’s paternal lineages have this marker.

My next paternal marker is the M42 version dated to around 80,000 years ago. This is still in East Africa but those with M42 would migrate from there to the north, south and west. Some M42s have not migrated that far and remain the traditional hunter-gatherers in the eastern Congo, the Mbuti pygmies who live in the Itun tropical rainforest (just 30-40,000 remain), the western Congo BiAaka pygmies (also around 30,000 remain) and the north-central Tanzanian Hadza who live around Lake Eyasi in the central Rift Valley and Serengeti (only 1,000 remain) – all have the M42 marker.

Mitochondrial Eve’s female descendants experienced genetic mutations that established two new distinct lineages designated as LO and the rather inelegantly named L1’2’3’4’5’6 group. Both these descendant groups are found only in Africa. The L1’2’3’4’5’6 group however, after further mutation, led to the creation of the L3 haplogroup around 72,000 years ago. This is in my maternal lineage. It also started out in East Africa. Many with L3 lineage remained in Africa and proved predominant in the Bantu-speaking groups of west-central Africa along the Niger-Congo where there are some 650 Bantu languages and dialects. L3s also dispersed south via today’s Mali to South Africa.

But for our purpose it is the L3 haplotype group which is specifically present in all the northern migrations that led out of Africa. Much later there would be enforced L3 migrations due to the Atlantic slave trade from West Africa to the Americas and Caribbean. For this reason L3 is present in many African-Americans too.

Plot of the mutation markers that describe the routes of my maternal antecedents (red) and paternal antecedents (blue) taken from Africa to Europe. The codes are the haplotypes, the numbers are the approximate number of years ago they would have been there.

The next mutation on my paternal side was the M168 marker occurring around 70,000 years ago in north-east Africa; my ancestor probably lived in Tanzania, Kenya or Ethiopia. M168 is present in every non-African man living today. This mutation occurred around the time there was a leap in human intellectual capacity that led us to develop tools and weapons and evolve a language.

My paternal ancestors appear to have migrated from the Horn of Africa crossing the 30kms (20-mile) strait (at the junction of the Red Sea and the Gulf of Aden) from today’s Djibouti and Eritrea into Yemen. Named the Bab-al Mandeb strait, it means ‘Gate of Tears’ derived from an Arab legend of the many who died when an earthquake separated Ethiopia and Arabia. Today almost 10% of the oil moved by tankers passes through this strait. I find it intriguing that my father spent time in Eritrea during WWII (RAF ground crew), though he could not have realised he was tracing his roots.

My paternal lineage then had a further mutation to create the P143 haplogroup at around 60,000 years ago. This was the first recorded to have happened outside Africa, if only just outside in the Jeddah, Mecca and Medina region of today’s Saudi Arabia. Around 55,000 years ago the M89 mutation occurred in the Middle East. Many remained where they were, others travelled through today’s Iran to the Caucasus and the steppes of Central Asia. One small group went north and through Anatolia to the Balkans. My paternal ancestor went north to the Black and the Caspian Seas.

In the meantime my maternal ancestors had travelled up the Nile valley or beside the Red Sea and crossed into the Sinai Peninsula. Here these northern L3 migrants generated further mutations around 60,000 years ago to form two new haplogroups, M and N, which between them would maternally populate the rest of the world outside Africa.

Around 50,000 years ago the M578 marker occurred on the present-day Iraq-Saudi border. One group of these set off eastward populating India and Southeast Asia and eventually reaching Australia; these were the ancestors of some of today’s Australian Aborigines.

My maternal lineage was the N haplogroup that originated around today’s Duba and Tabuk in Saudi Arabia. After a few thousand years settled in the Levant these ancestors once more pursued the migrating game. Some migrated westward through present-day Turkey and the eastern Mediterranean, others went eastward through central Asia to be found in the Indus Valley. My maternal antecedents however spread north through today’s Jordan, Syria, Iraq and Iran. My mother’s ancestors then travelled up towards today’s Tabriz in north-west Iran where the next mutation happened some 55,000 years ago to generate the haplogroup R.

The next maternal mutation occurred at 47,000 years ago creating the U haplotype. These were my mother’s antecedents who continued northwards past the Caspian Sea to its west and through today’s Armenia, Azerbaijan and Georgia. They then turned westward passing above the Black Sea through today’s southern Russia.

The K haplotype occurred some 27,000 years ago in today’s Ukraine near Mariupol, followed by the K2 marker 21,000 years ago. The K2a marker happened around 11,500-6,800 years ago at the time when PPNA (Pre-Pottery Neolithic A) groups were emerging, the very beginnings of the archaeological record.

Meanwhile my paternal lineage had its next mutation, the P128 haplogroup, 45,000 years ago and some distance north of today’s Kabul on the Afghanistan-Tajikistan border. Half of all non-Africans derive from this lineage. The P128 haplotype then split three ways – into the O group that is the most common in East Asia, the Q group that is the major lineage in the Americas, and ‘my’ R group, the major lineage in Europe and Central Asia. My paternal lineage appears to have added the M526 mutation and continued eastward into western China some 42,000 years ago.

Some 35,000 years ago the M45 mutation saw my paternal lineage moving in small big game hunting groups onto the open savannah, travelling north-west across Kyrgyzstan and Kazakhstan. M45 went on to create the Q and R groups (see above) that eventually populated the planet. One M45 descendant group is mostly found in India – the Saora from Andhra Pradesh, the Bhumji from Assam, West Bengal, Odisha and Jharkhand and Muslim groups in the far north-east of Manipur.

Around 30,000 years ago the M207 marker would be the stepping stone to several important groups, though none of them mine –the R-M432 from which most western European men derive and R-L62 which is common in eastern Europe and India.

My paternal lineage went down the P231 route around 25,000 years ago as they travelled across southern Russia and Belarus into Europe collecting new markers as they went. Research is still ongoing and the next five markers in my male lineage present a confused picture:

  • M343 emerging 22,000-17,000 years ago represents 7% of Russian males (including Tsar Nicholas II), 13% of males in the Balkans, 21% of Eastern Europeans, 43% of Central Europeans and 55-58% of Western Europeans
  • M269 between 15,000 and 6,500 years ago is present in 5% of males in Kazakhstan, 6-8% of those in Turkey, 13-14% of Greeks, 32% of Germans, 85% of the Welsh and 90% of east-coast Irish
  • P310 is present in just 1-2% of males in Iran, Kazakhstani and Lebanon, 5% in Oman, 8% in Italy, 38% in Spain, 45% in France and 48-52% in Ireland
  • U106, from as early as 14,000 until 4,250 years ago, appears strong in Benelux – 14% presence in the Netherlands, 13% in Luxembourg and 12% in Belgium – just 6-9% in the UK, 4-5% in Cyprus and just 1-2% in Italy and Spain
  • L48, 7% of Belgian males, 4% of Netherlands, 3-4% in England, 3% in Denmark and Switzerland and 2-3% in Germany. The geneticists provide a ‘heat map’ that shows U106 is particularly present in Western Europe.

I don’t believe there is any way that I can seek to fill the gap from DNA’s 2,500 BCE to Sims of Yetherham in 935 CE.

So here ends my ‘accompt’. John Denton wrote his in Cumberland in 1603, mine is completed in Oxfordshire in 2016. If it turns out the next has the same interval I wonder where in 2400 it will be prepared, in what format – and whether the author will be a Robert Soulsby Denton?

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