THE ORIGINS OF US ALL—BY DNA GENETIC ANALYSIS
As a follow-up to the thread “On the origins of Charles Darwin—by Genetic Genealogy”, readers who have had their DNA evaluated may discuss theirs here if they wish.
We would be interested to hear such stories of analytical deduction if you want to tell us.
HERE IS A CASE STUDY
So here follows a case study—the story of my male-line DNA which is summarised to demonstrate the possibilities that are open to everyone. The DNA haplogroups were evaluated by scientists at www.familygenetics.co.uk
Two forms of 'deep ancestry' testing are available—via the Y and the X chromosomes. The Y chromosome is carried by the paternal male line (i.e. father to father to father). The other is the mitochondrial DNA in the X chromosome—the maternal female line (i.e. mother to mother to mother).
For both, DNA specialists provide information about the geographic regions and dispersals of one’s remote ancestors. As the science of DNA improves, the results become ever more informative as to when and where the ancestors may have lived.
There are many useful books on the subject, and excellent web sites too. The book Blood of the Isles by Bryan Sykes gives a very readable account of how results can be obtained and interpreted.
Stephen Oppenheimer’s The Real Eve (documentary and US book title) / Out of Eden (UK book title) are excellent.
My male-line DNA story --- haplogroup I1b2a — as carried on the Y-chromosome.
This group, I1b2a, is uniquely European—and widely found among the British, Iberians and Basque, Italians, and Sardinians.
The minor later mutation I1b2a1 is entirely British—a direct descendant from the I1b2a carriers who walked into peninsula Britain in the post-glacial, pre-island-Britain, pre-Neolithic era.
And of course there are Americans known to have I1b2a and I1b2a1 on account of post-16th century emigration from Britain.
HERE’S A SUMMARY OF PREHISTORIC MOVEMENTS AND MUTATIONS
First there was the primary ‘Eve’ who bore the crucial founding mutation of the Homo sapiens species. This was some time around 200,000 /190,000 years ago when haplogroup A and then B emerged in Central Africa. By about 130,000 years ago, these populations occupied all Africa.
In the course of time—and still in Africa—the human genome changed again and again (→ C, D, E).
Palaeo-anthropological and archaeological evidence shows that modern humans were in the Near East and Middle East of Asia by between 100,000 and about 70,000 years ago.
The DNA of people who had left Africa mutated to a fresh primary haplogroup called F.
Haplogroups from G to R are branches of F. This means that most people in Europe and the Middle East are descendants of the founder of group F.
Eventually by 20,000-15,000 years ago the Palaeolithic founder of the ‘I’ primary haplogroup appeared in the Balkans, but human progress northwards across Europe was interrupted by the intensifying cold of the Last Glacial Maximum. The Alps were totally ice-bound, so the migration routes westwards were limited to coastal Italy and south-coastal France. The I1b development happened in the Balkan-period refuge at about 15,000 years ago. Descendant I-subgroup variants (I1b1, I1b2, … etc.) appeared in the general western Mediterranean region from the Balkans and Italy to Iberia between 15,000 and 12,000 years ago.
As the ice retreated (from 12,000 years onwards), and tundra was replaced by plains and woodland across France and then Britain, members of the ‘I’ sub-groups (I1a, I1b2, … etc.) [along with subgroup variants of other haplogroups of course] spread from Spain and the Mediterranean as they pursued migrating herds northwards towards Britain. Hence it came to pass that a small population of a particular group-I mutation, I1b2a, who had settled probably in northern Iberia were the ancestors of my own I1b2a family members. We surmise this because sub-group I1b2a is found not only in Sardinia, Italy and the Franco-Spanish-Basque region, but also up the west coast of France and into England where they would have arrived on foot.
That so many I1b2a subgroup people are in Britain implies that bearers of this subgroup, as Mesolithic hunter-gatherers, got there between 10,000 and 8,000 years ago before the land-bridge between the continent and Britain was cut around 8000 years ago (6000 BC) by rising seas caused by polar ice melt. This isolated them, and as for the fewer later peoples (4000 BC onwards, including those bringing seeds and animals from the Continental Neolithic) they could only arrive by boat.
THE AMERICAN INTEREST. Over the last four centuries huge numbers of Europeans have migrated from Britain, Ireland and the European continent to the Americas. All manner of haplogroups are represented. This is why it is worth obtaining your own DNA analysis in order to learn about your personal deep-prehistoric ancestry.
* FEMALE LINE: It is much the same with my female line which is haplogroup U3 in the X-chromosome. This evolved around 20,000 years ago by mutation in the Ice-Age ‘refuge’ of the Ukraine. After the ice had retreated, U3 hunter-gatherers eventually reached England, borne by peoples who migrated north and west across Poland and northern Germany and arrived before the land-bridge into Britain was severed.
** Interestingly, another U group (namely, U5a) is the group shared by both school-teacher Adrian Targett of Cheddar (Somerset, south-west England) and the 10,000 year old skeleton found in a cave in his village in Cheddar Gorge. They have identical DNA which indicates how stably settled some families have been throughout this very long time interval.
*** Amazingly my wife’s maternal group is U5a1—and that interesting story can be briefly related another time.