Sunday, August 12, 2012

The family DNA - Y-chromosome initial results

Back in June I began what I expected to be a very short series of posts on archeological and biological reasons for deciding when Europeans first came to America. It was motivated by the more European look in early illustrations to the Eastern Native Americans, as opposed to the more Asian look of those further to the West.

As I began to research the topic, however, a number of distractions began to appear, and took time to look into. I have now read about a dozen books on related topics, as well as visiting many Web pages. The study has rekindled my interest in my own ancestors, and I have scraped my cheek, and will soon spit into a tube, as ways of seeing what my own DNA will reveal. In the process of doing all this it seems as though, when my generation and the baby boomers who follow, reach a certain age we get more interested in the past. Thus the apparent growing success of the two recognized sites that provide autosomal DNA testing as well as the mitochondrial and Y-chromosome evaluations that have been the more traditional sources. (I base that on Bryan Sykes’ opinion in his book “DNA USA:A Genetic Portrait of America".) Professor Sykes is former Professor of Human Genetics at the University of Oxford, and Chairman of Oxford Ancestors, a UK firm providing DNA services. The two American sites are Family Tree DNA and 23andme. There will be a separate post to explaining the strides that have been made in the last decade in DNA testing, and why, for example, without seeing more than her DNA sample, the Actress could be told by one of these companies that she had brown eyes and curly hair (which she does), among other interesting information.

I began our own DNA study after reading Spencer Wells’ book “Deep Ancestry: Inside the Genographic Project". Dr. Wells is an Explorer-in-residence at National Geographic, and has been the person most clearly identified with the Genographic Project run by National Geographic, which takes samples of the DNA of different groups and ties them into the spread of mankind from their origins in Africa. The story he told was sufficiently intriguing that I persuaded my sister, the Nurse, to scrape her cheek and to send her sample off with mine to that program.

The reason to do both comes from the two different lines that can be traced back most easily for an individual. These are, for males, based on the Y-chromosome and parts of its structure that do not change from generation to generation, except only through variations that occur at very infrequent intervals Thus, in the particular part of the Y-chromosome that is studied, I carry the same information string as my father, and his father, and so on back through time. (The next post will deal with the mitochondrial DNA line through my sister, that marks the maternal descent).

Figure 1. The passing of Y-chromosome information from generation to generation. (By convention squares are male and circles represent females, and each line down represents a generation).

Because daughters do not inherit the Y-chromosome (otherwise they would be sons) a lineage can “daughter out” if all the children across a line are female, since there is then no path for the male lineage to continue – through that line – but, as I will explain in the next post, there is a part of the male ancestor that still makes it through, albeit in a different form in the autosomal DNA. (And if you want to read ahead you might look at Charts, Graphs and Diagrams).

Thus, by sending away the scraping from my cheek to the Genomic Project I received, about six weeks later, notification that my results had been posted. (The information is passworded and only that which I have approved gets used in the program, with as much anonymity as I seek to have. But, as you may note by my writing about it, I have chosen, for reasons I will later explain, to be quite public).

The information that I received was, relative to all that I now know is available, somewhat cursory. Simplistically it showed the path that my own particular ancestors trod, following the time of the male common ancestor (referred to as Y-chromosomal Adam) who lived about 60,000 years ago.

Figure 2. Path of my ancestors from the time of Y-chromosomal Adam until about 20,000 years ago. (I come from the Cro-Magnon line).

Simplifying the report, relative to the above path, my basic haplogroup (the term for the classification group for my DNA, of which more later) is haplogroup R1b, M343 (Subclade R1b1a2, M269). It is the most common group in Southern England, where 70% of males fall into this category. But the part where we reached England is not covered in the initial National Geographic report. Rather they just spell out the bit that led to Cro-Magnon man.

From the earliest time in Africa the group in which I fall started with a modification M!68 to the initial DNA. At that time, roughly 50,000 years ago there were believed to be only around 10,000 people of the homo sapiens type. And the group was thought to originate in the Rift Valley from which the individual with this marker moved up and out of Africa. The marker is carried by every non-African man today.

A second distinctive marker (M89) developed some 45,000 years ago, as the human tribes began to follow the herds of game into the plains of Central Asia. It is this herd following practice, which led into the herding cultures of the Lapp and other northern tribes across the Arctic perimeter and which, I believe, hastened the speed at which some of these migrations occurred. Although, as Spencer Wells notes in the video “The Human Family Tree” even if the migrations moved at only a mile a year, they had plenty of time to reach the different points along the way, in either the route shown above, or to more distant places such as Australia.

While some did move on to Australia (having had to develop ways of crossing the sea to get there) a smaller group (including us) moved further north and across the mountains and this group with the M9 marker, which developed around 40,000 years ago, spread over much of Eurasia.

The mountains divided the tribes here, some moved further East, to Siberia and then on to America, others went down to India, and others north of the Hindu Kush where the advancing glaciers of the time (about 35,000 years ago). The M45 marker is found as mankind was learning to make tools of other materials than just stone. Smaller flakes made it easier to make more precise tools, and needles were made from bone to make warmer garments.

With the growing cold my ancestors, now also carrying an M207 marker moved west. Some turned south down towards India, but the remainder move towards what is now Europe bringing a new marker M173 to mark their distinction. These were the first of the homo sapiens line to establish in Europe, where Neanderthals had predominated. (And for those wondering what happened to them, there was at least some inter-relationships since the average person today carries between 1 and 4% of the Neanderthal DNA.)

As my National Geographic report states:
This wave of migration into Western Europe marked the appearance and spread of what archaeologists call the Aurignacian culture. The culture is distinguished by significant innovations in methods of manufacturing tools, more standardization of tools, and a broader set of tool types, such as end-scrapers for preparing animal skins and tools for woodworking.

In addition to stone, the first modern humans to reach Europe used bone, ivory, antler, and shells as part of their tool kit. Bracelets and pendants made of shells, teeth, ivory, and carved bone appear at many sites. Jewelry, often an indication of status, suggests a more complex social organization was beginning to develop.
The onset of the Last Glacial Maximum drive humans south, into Spain, where they gave birth to Cro-Magnon man, who carried the M343 marker (as do I) and it is there that the National Geographic report ends. At the time of Cro-Magnon man, as Brian Fagan notes in "The Long Summer" were still hunting reindeer as they migrated through the passes, as the herds migrated through the valleys of south-west France. Ice at the time covered most of the UK.

Figure 3. The extent of ice during the last Glacial Maximum.

One of the options that National Geographic provides is that you can then send your sample to Family Tree DNA for further analysis, and for comparison with a broad range of other individuals who have sent in their samples. I have done that, and in future posts will let you know how that went, as well as passing on some of the information that we got from the maternal side of the blanket, through my sister's DNA, and also for the Actress and how they knew she has brown eyes.


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  2. While a lot of DNA contains information for a certain function, there is some called junk DNA, which is currently used for human identification. At some special locations in the junk DNA, predictable inheritance patterns were found to be useful in determining biological relationships.DNA Testing Immigration

  3. Very interesting, but if you have Cro Magnon, why don't you look part black? Cro Magnon are part black, part white. A mix of Neanderthal and Homo Erectus. Are you sure you understood that right, and aren't just tracing the Neanderthal male through the Cro Magnon male?