Rationale for Data Bank Development and Dissemination
In some ways the splendor of creation is infinitely variable. Every flea, every rhinoceros, every crab, every human that has ever lived has been a unique individual. On the other hand there is an amazing amount of identity between all living things. Every human that has ever lived has shared about 70-85% of his or her genes with every other that has ever lived. Every living thing that has ever lived shares aspects of the same genetic code. This paper is about one aspect of this sameness/difference duality. That aspect is the sameness/difference of gender-linked genetics among all humans. More specifically, I will be describing the results of some research I have undertaken concerning the gender-linked chromosomal history of the entire human race (subject to the constraints of available data) and to reveal some interesting facts about that history. I do not attempt to interpret these facts, only to present them for further study.
The foundation upon which this research builds is the work of the many geneticists who have been developing the field of ancestral genealogy. These trailblazers have constructed a theory that all of humanity can be categorized according to a fairly small number of mutations on the two gender-linked chromosomes. These chromosomes, the mtDNA in women and the Y-DNA in men, pass largely intact from generation to generation, such that the version of the corresponding genes in your body right now are essentially the same ones that were in the body of one of your nth degree grandparents going from mother-to-mother or father-to-father back until the very first human individual that ever lived. I say essentially because along the way there have been a few mutations. Each one of these mutations helps us to sub-categorize your genes according to which mutations appear in your copies of these genes. For example, say about 54,000 years ago there was a human being living his life somewhere along the Rift Valley of Eastern Africa and for some reason, one of this individual’s sons was born having the M60 mutation on the Y-chromosome. The label M60 is one of many generally accepted categorization markers (see Clade Markers page) used to define membership one or other of these sub-categories. Essentially what that means is that at one specific location of Y-DNA, this individual and all of his offspring share that same mutated genetic coding and will continue to do so until another mutation happens to shake things up at that precise spot. So, if you have the M60 mutation in your Y-DNA you can rest assured that you are the direct male descendent of the first M60 mutant-- the odds of the same mutation arising separately in two unrelated individuals are far too remote to even consider. You may also have other mutations that this original M60 character did not have and these could be used to further refine your ancestral genealogy. For instance it could be that 5,000 years ago, another mutation giving rise to the M236 marker took place and all the descendants of that individual now have both the M60 and the M236 mutations. A similar historical narrative can be done using the mtDNA mutations.
As I mentioned from the outset, I do not know whether sharing the M60 mutation has any implications beyond simple happenstance. Could there be a physiological, psychological, behavioral, historical, cultural or any other complex phenotypical implications (i.e., traits) that come from partaking of this genetic ancestry? Do gender-linked genes affect any aspect of our cultures or our individual characteristics? Is there evidence of group selection to be found here? Do the data contain environmental implications (this being my focus of study)? I don’t know the answers to these questions and it is still too early in the development of this field to tell with any certainty (part of the motivation behind this study is to begin this process). I strongly advise all readers to make themselves aware of the analytical risks of jumping to hasty conclusions at this early stage of the inquiry (please see the section on risks, assumptions, and potential errors).
One thing I can say based on my own research is this: haplogroups of a feather tend to flock together (haplogroup is another way of saying ‘all those people carrying a specific set of gender linked mutations’). In studying the ancestral origins of today’s global population, one finds that the way things have tended thus far is towards populations of similarly mutated individuals rather than populations of mixed up mutants. To contextualize this with our example, M60 individuals tend to live in populations with other M60 individuals. Although each of these M60 individuals is unique with respect to their entire 23 chromosomes, as far as their gender-linked chromosomes are concerned, they are the same. So for instance, if one takes a sample from, say, Spain, one would discover that about 60% of the men there share the M207 mutation. You would also find that about another 13% share the M96 mutation and about another 7.25% share the M170 (nearly 80% of the men in Spain carry one of these three mutations).
A similar pattern is manifested in each nation of the world, such that for about 66% of the nations of the world, more than 50% of the individuals in the population belong to a single major haplogroup. For about 99% of the world’s nations, more than 50% of the individuals in the population belong to two major haplogroups. Let me say that again, in 66% of countries, a single haplogroup constitutes the majority of people living in that nation, while in 99% of countries, two haplogroups constitute a majority of the people living in that nation. This may seem obvious in places like Finland, where most of the people are what we would call Finns. But it also holds true for large, multi-ethnic, and diverse countries like India, China, the United Kingdom, Congo (Kinshasa), Egypt, and the USA. In fact, only in Sri Lanka, among the world’s nations, do the two most common haplogroups within the country fall short of constituting a majority. I cannot help but think that these facts reflect some monumental aspect of pre-history, clouded in mystery perhaps forever. The myriad findings I now present seem to me to be profound, far-reaching, and rich with hidden meanings; due to my own epistemic and temporal limitations I will present them unadorned and let them speak for themselves.
Cherson AD (2012)
Atlas of Genetic Genealogy