Environmental Setting of My Ancestors

Haplogroup O is mostly found among populations in East and Southeast Asia and mostly associated with the Chinese people and the main Han Chinese lineage of which I am a part. Moreover, Haplogroup O is also marked, along with its corresponding DNA markers, by Sino-Austronesian languages

The largest and most dominant component of the East Asian Y chromosome gene pool, Haplogroup O accounts for 75% of the total paternal lineages of Chinese. Yet, it is almost nonexistent in Western Siberia, Western Asia, Europe, and Africa and is completely absent from the Americas.

Figure 3
Haplogroup O

Haplogroup O Map

Haplogroup O originated 35,000 years ago during the Ice Age in the East/Southeast area of present day China where researchers are finding the skeleton remains of prehistoric Asians as well as new archaeological and paleoclimate data. They are studying the cultural patterns, lifestyles, and individual mobility of these prehistoric inhabitants. This is also the area of origin of my earliest genetic ancestors (hereafter, I will just use the term ancestors) ~30,800 years ago during the time of the Last Glacial Maximum of the Ice age.

Figure 4
Animation of Ice Age Coverage

Ice Age image

Figure 5
Ice Age Man

To give dimension to life in my ancestor's time, the Ice Age glaciers were at their thickest and living was harsh. He would have contended with thick year-round ice sheets, frigid climate, and dwindling hunting and foraging spaces. To keep warm in the cold climate, he wrapped himself in animal skin. He also chose to take shelter in the warmth of caves, staying near the mouth of the cave where it would be lighter for better vision. Where no caves existed, he built temporary shelters from branches, leaves, and animal skins. As part of a clan of hunter-gatherers, he found food by hunting and fishing. He also gathered edible plants, fruit, and collected eggs from bird nests. A single kill of a woolly mammoth by the clan was a big plus. It could be their food for months.

To add context to the world of my early ancestors, they lived among other types of human beings, which is relevant to my genome. At some point, my ancestors encountered these other archaic humans and not unexpectedly, interacted with them. Both Neanderthal and Denisovan DNA markers are present in modern Asian populations, including mine. My genome includes 1.4% Neanderthal and 1.8% Denisovan.

Figure 6

Neandertal-Denisovan image

Neanderthals and other humanids, such as the Denisovans had long interbred with Asians as noted in this video. Deniovans wandered Asia for hundreds of thousands of years and remained in existence as recent as the time of my ancestors. Their genes are found in modern East Asian populations and the Oceanic islands and records show Denisovans interbred with early modern humans in Southeast Asia, particularly among the modern residents of the Pacific islands, including the Philippines and New Guinea. "As a result of ancient interbreeding, people living today on islands of Southeast Asia and Oceania have genomes with up to 6 percent Denisovan DNA." Furthermore, Clare Wilson points out "Our species may have been interbreeding with Denisovans as recently as 15,000 years ago." To that end, genetic analysis uncovered a direct descendant of two different groups of early humans with the now proven existance of humans with a Neanderthal mother and a Denisovan father.

A report of the other hominids living along side Neanderthals and Denisovans in southeast Asia can be viewed in this video. A research team led by David Reich discovered at least three major waves of human migration into the South Asia over the past 50,000 years and during that time the anatomically modern hunter-gatherers in Southeast Asia interacted with the ancient human Homo erectus, Homo floresiensis, and Denisovan " populations. Moreover, in addition to (Homo floresiensis) in Fores in indonesia, other hominids lived in the area as well, such as in present day Luzon in the Philippines with (Homo luzonensis). Current evidence suggests that Southeast Asia was occupied by Hoabinhian hunter-gatherers until about 4000 years ago.

Figure 7
Homo luzonensis

My early ancestors also lived in a time when many of today's Southeast Asia islands were still above sea level. They were connected to the Asian mainland to form the continent of Sundaland. It was twice the size of India and it stretched east to west from Burma to Borneo and included present-day Malaysia and Indonesia. In essence, Sundaland joined the islands of today's Southeast Asia into a single great landmass, extending all the way to the Philippines.

Figure 8
Ice Age Asia
with Sundaland above sea level

Ice Age Asia

Figure 9
Animation of Sundaland
Slowly Sinking Below Sea Level

Sundaland in Asia Sinking

While the extensive savanna of Sundaland remained above sea level my ancestors would have adapted to this environment and likely settle on the broad riverine flood plains and, in time, integrate with the existing communities.

At the time, ~29,400 years ago, my descendant of the O-M175 ancestral lineage experienced a genetic variation which resulted in his acquiring a genetic trait his ancestor didn't have, in essence, a new genetic marker. So this new descendant joined the existing O-M122 branch of Haplogroup O. Specifically, the ancestor to which the O-M122 marker refers to is known by the acronym Most Recent Common Ancestor (MRCA), but only for the O-M122 branch of my haplogroup. As such, he is the person who is the most recent man from which all the men in my haplogroup branch are directly descended.

So, I know when this MRCA lived, but only generally where he lived. Continuous migrations of the O-M122 ancestral line makes the specific geographical location of my O-M122 ancestor ambivalent. Possibly he existed in the general vicinity of present day the Hubei Province in China known for the Three Gorges and the Yangtze River. It is the longest river of Asia and China and believed to be the cradle of ancient civilizations. The Yangtze forms the boundary between present day northern and southern China. The Yangtze River plays an important role in China's culture and long history of civilization. Many cultural heritage sites are located along the Yangtze River.

The O-M122 marker is the main sub lineage of O-M175 and as such, O-M122 is the predominant sub-group in China and has spread into Taiwan with high frequency among the existing aboriginal Taiwanese population, and into Indonesia, Melanesia, Micronesia, and Polynesia. So, finding the geographic location where my O-M122 ancestor originally lived is difficult. All that is known with certainty is my ancestor bears a Southeast Asia marker in the proximity shown in Figure 8. He is but one among a multitude of those bearing the same marker over the ages and who may have lived in different places in the centuries following its genetic origin. Still, as Caitlin Dempsey reports, efforts continue to pinpointing the geographic origin of a person's ancestry. The belief when a marker is formed it can be linked to a geographic location and to group populations with the same marker by point of origin.

Today, men bearing the O-M122 marker are present in large numbers in China, Indonesia, Thailand, Vietnam, Malaysia, Cambodia, Philippines, Taiwan, Myanmar, and Laos in that order.

With the passage of time,my haplogroup O lineage would again evolve with the appearance of another ancestor bearing the DNA Marker O-P201 ~23,200 years ago in China's Yagtze River Delta in the general proximity of present day Chongqing..

It might have been the harshness of ice age weather that prompted my O-P201 ancestor's migration south. The global cooling drove both animals and man south, and likely resulted for the emergence of my O-P164 ancestor ~19,200 years ago. This pattern of genetic variation among my subsequent ancestors would be largely shaped by continued human migration into Southeast Asia. Their journey may have even been overland into the continent of Sundaland, which would not wholly sink under the sea until ~12,000 years ago.


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