Peopling Of The Americas- Rapid Settlement And Substantial Lineage Extinction Upon European Contact

Here is the full paper : Ancient mitochondrial DNA provides high-resolution time scale of the peopling of the Americas

The exact timing, route, and process of the initial peopling of the Americas remains uncertain despite much research. Archaeological evidence indicates the presence of humans as far as southern Chile by 14.6 thousand years ago (ka), shortly after the Pleistocene ice sheets blocking access from eastern Beringia began to retreat. Genetic estimates of the timing and route of entry have been constrained by the lack of suitable calibration points and low genetic diversity of Native Americans. We sequenced 92 whole mitochondrial genomes from pre-Columbian South American skeletons dating from 8.6 to 0.5 ka, allowing a detailed, temporally calibrated reconstruction of the peopling of the Americas in a Bayesian coalescent analysis. The data suggest that a small population entered the Americas via a coastal route around 16.0 ka, following previous isolation in eastern Beringia for ~2.4 to 9 thousand years after separation from eastern Siberian populations. Following a rapid movement throughout the Americas, limited gene flow in South America resulted in a marked phylogeographic structure of populations, which persisted through time. All of the ancient mitochondrial lineages detected in this study were absent from modern data sets, suggesting a high extinction rate. To investigate this further, we applied a novel principal components multiple logistic regression test to Bayesian serial coalescent simulations. The analysis supported a scenario in which European colonization caused a substantial loss of pre-Columbian lineages.

Several points of interest come to mind.

a) Separation with Siberian common ancestors took place about 24 thousand years ago, followed by a long period of isolation in Beringia (see Fig.).

The founder lineages then settled the America's quite rapidly beginning around 16 thousand years. Sites in Chile show human habitation by 14 thousand years.

b) The much talked about Clovis culture were not the first Americans.

c) There was a demographic collapse among the Native American populations. Charles Mann's 1491 gives quite a sweeping account of both native and Spanish eye witness accounts of the wiping out of entire tribes and communities due to Old World diseases. This paper backs that up using genetics. A comparison of ancient DNA with present day Native American DNA shows that extensive extinction of mitochondrial lineages took place.  In plain language, entire tribes were wiped out to be replaced  much later by natives migrating from some other place, although the authors caution some of the discontinuity of lineages could be because  modern diversity may have been undersampled.  The data for ancient DNA comes principally from the western coast of South America which had large Native American population centers.   Lowland populations went extinct more. Highland populations were less affected. Perhaps population contact was more in the lowlands and diseases like malaria more prevalent in the warmer climes?

Amazonia Before Columbus

This is an interesting article published in the Royal Society's Proceedings B.

During the twentieth century, Amazonia was widely regarded as relatively pristine nature, little impacted by human history. This view remains popular despite mounting evidence of substantial human influence over millennial scales across the region. Here, we review the evidence of an anthropogenic Amazonia in response to claims of sparse populations across broad portions of the region. Amazonia was a major centre of crop domestication, with at least 83 native species containing populations domesticated to some degree. Plant domestication occurs in domesticated landscapes, including highly modified Amazonian dark earths (ADEs) associated with large settled populations and that may cover greater than 0.1% of the region. Populations and food production expanded rapidly within land management systems in the mid-Holocene, and complex societies expanded in resource-rich areas creating domesticated landscapes with profound impacts on local and regional ecology. ADE food production projections support estimates of at least eight million people in 1492. By this time, highly diverse regional systems had developed across Amazonia where subsistence resources were created with plant and landscape domestication, including earthworks. This review argues that the Amazonian anthrome was no less socio-culturally diverse or populous than other tropical forested areas of the world prior to European conquest.

I had read 1491 by Charles Mann so none of this came  as a surprise  to me. I would recommend Mann's book  too.  It is a very well researched richly detailed book on the human landscape of the America's (south and north) before the European conquest. The Amazon basin is covered too and the two things that stuck with me are the "anthrosols" or soils produced or rather enriched in organic matter and nutrients by humans activity like mulching and composting. The map below shows the distribution of these anthropogenic soils.

 Source: Clement C.  et.al. 2015

Their concentrations along the banks of rivers match early European descriptions of farming communities settled along river bluffs, with the interfluvial areas being occupied by semi-nomadic and nomadic hunter gatherers.

The other aspect that fascinated me was the observation of Europeans of the incredibly varied fruit trees from the Amazon jungles. Many true wild fruit are generally small, sour, bitter, thorny, spiky. The native people over millennia had transformed them by selective breeding into the edible fruit smorgasbord that one sees today. Imagine large areas of "virgin" Amazon forests were actually abandoned fruit orchards!

Read this article though.

Kaolinite And Chinese-Mexican Pottery In 1600's Mexico

 My Book Shelf # 25

As with a previous post which pointed to the role of silver as a catalyst for the movement of people across the oceans and a meeting of Asia with the America's in 1600's Mexico, geology in the form of clay deposits played a role in bringing full circle the story of Chinese (Ming) influence on Mexican ceramic art from the mid 1600's onwards.

The district of Puebla in Mexico has kaolin deposits of exceptional quality formed mostly by the hydrothermal alteration of a rhyolitic host rock from the Late Cenozoic Trans Mexican Volcanic Belt considered to part of the Circum-Pacific volcanic chain. This type of clay is used extensively in pottery.

By the late 1600's Puebla city had a tight knit Asian community:

One of the city's most important industries was ceramics - Puebla clay is of exceptional quality. Working with eye-straining attention to detail, skilled potters created pieces that imitated blue-and-white Ming dynasty porcelain. Guild regulations specified that "the coloring should be in imitation of Chinese ware, very blue, finished in the same style". Edward Slack, the Eastern Washington historian, points out that the manufacturers would hardly have ignored the skilled Asian craftspeople in their midst. More than likely, Puebla's fake Chinese pottery was created in part by real Chinese potters. If so, they did a splendid job: talavera ware, as it is known today, is now so highly prized that when I visited Puebla shopkeepers complained that the country was fighting an invasion of counterfeits from China - a Chinese imitation of a Chinese-made Mexican imitation of a Chinese original. 

From 1493: Uncovering The New World Columbus Created by Charles Mann.

Mexican Silver And Japanese Samurai

 My Book Shelf # 24

A post by Metageologist on tracking the source of silver in English coins from Medieval to early modern times caught my eye.

Silver formed by different geological processes may have distinct isotopic signatures. Metageologist points to a study which recognized English silver coins being sourced initially from silver taken from European mines and then later from the mid 1500's from Mexico via the Atlantic trade route. The silver from rich deposits in Peru primarily took the Pacific route and went to satisfy Chinese demand.

People too moved across continents along with silver. I came across this fascinating passage from 1493- Uncovering The New World Columbus Created by Charles Mann on the outsourcing of security for silver shipments-

Known collectively as chinos, Asian migrants spread slowly along the silver highway from Acapulco to Mexico City, Puebla, and Veracruz. Indeed, the road was patrolled by them- Japanese samurai perhaps in particular. Katana-swinging Japanese helped supress Chinese rebellions in Manila in 1603 and 1609. When Japan closed its borders to foreigners in the 1630's Japanese expatriates were stranded wherever they were. Scores, perhaps hundreds migrated to Mexico. Initially the viceroy had forbidden mestizos, mullatos, negros, zambaigos, and chinos to carry weapons. The Spaniards made an exception for samurai, allowing them to wield their katanas and tantos to protect the silver shipments against the escaped-slaves-turned-highwaymen in the hills.

Charles Mann is right when he calls the Mexico of this period a "crazy soup".

A Warning From A Chinese Thomas Malthus

My Book Shelf # 23

In 1793 Hong Liangji, a bureaucrat in the Qing empire had an idea. He had been sent as an education inspector to Guizhou Province in the southwestern part of China. The arrival of crops from  the Americas like maize, potato and sweet potato, capable of thriving in marginal soils and steeper slopes, meant that more areas were coming under the plough and China was experiencing a population boom.

Hong Liangji worked out the consequences for a 8 person family:

Eight people would require the help of hired servants, there would be, say, ten people in the household. With the ten-room house and the 100 mu of farmland,  I believe they would have just enough space to live in and food to eat, although barely enough. In time, however, there will be grandsons, who, in turn, will marry. The aged members of the household will pass away, but there could still be more than twenty people in the family. With more than twenty  people sharing a house and working 100 mu of farmland, I am sure that even if they eat very frugally and live in crowded quarters, their needs will not be met. 

Hong conceded that the Qing had opened up new land to support China's population. But the amount of farmland had 

only doubled or , at the most, increased three to five times, while the population has grown ten to twenty times. Thus farmland and houses are always in short supply, while there is always a surplus of households and population... Question: Do Heaven-and-earth have a way of dealing with this situation? Answer: Heaven-and-earth's way of making adjustments lies in flood, drought, and plagues. 

Hong had described the Malthusian trap 5 years before the idea came to Thomas Malthus. He not only predicted that standards of living will stagnate as population increase outstrips resources but that there will be ecological consequences of the relentless drive to deforest and reshape the landscape for growing more and more food.

From 1493: Uncovering The New World Columbus Created  - Charles Mann.