My Y chromosome identifies me as a member of haplogroup G2, a lineage defined by a genetic marker called M201 for G and P15 putting me in the subclade 2. (Negative for M285 M286 M287 M342 M377 and P20). This haplogroup is the final destination of a genetic journey that began some 60,000 years ago with an ancient Y chromosome marker called M168. The very widely dispersed M168 marker can be traced to a single individual—"Eurasian Adam." This African man, who lived some 31,000 to 79,000 years ago, is the common ancestor of every non-African person living today. His descendants migrated out of Africa and became the only lineage to survive away from humanity's home continent.
Population growth during the Upper Paleolithic era may have spurred the M168 lineage to seek new hunting grounds for the plains animals crucial to their survival. A period of moist and favorable climate had expanded the ranges of such animals at this time, so these nomadic peoples may have simply followed their food source. Improved tools and rudimentary art appeared during this same epoch, suggesting significant mental and behavioral changes. These shifts may have been spurred by a genetic mutation that gave "Eurasian Adam's" descendants a cognitive advantage over other contemporary, but now extinct, human lineages.
The M201 lineage that defines an uncommon haplogroup called G, which is rarely present in population frequencies at greater than a few percent. Genealogists believe that this line of descent first appeared in northern India's Indus valley, on the M89 lineage, and subsequently dispersed during the past 10,000 to 20,000 years.
Currently, little else is known of haplogroup G's origin or history. Learning more about such unusual lineages is a primary goal of the Genographic Project and the Y search which helps researchers with results from Family Tree DNA