The Spanish conquest of the Americas was devastating for native peoples. Many native men died in conflicts with the invaders. Male Spanish colonists often came without their wives and took native women as partners. A new genetic analysis of Panamanian men by a team including a Smithsonian scientist shows this historical legacy: only 22 percent had Y-chromosomes of native origin, even though most Panamanians are of female indigenous ancestry.
Everyone has a pair of sex chromosomes that determine their gender. Females have two X-chromosomes, while males have one X and one Y, the latter inherited from their father. These chromosomes are found in each cell's nucleus. Another genetic component called mitochondrial DNA (mtDNA) is found in cells outside the nucleus. Both males and females inherit their mtDNA from their mother alone. Over time, small mutations accumulate in both mtDNA and Y-chromosomes, allowing scientists to trace their history.
A team of geneticists from the University of Pavia including Antonio Torroni found that among the 408 Panamanian men whose genetics were analyzed, 60 percent had Y-chromosomes that originated in West Eurasia and North Africa (probably mostly from Europe). About 22 percent were of Native American origin, 6 percent from sub-Saharan Africa and 2 percent from South Asia (probably China or the Indian sub-continent). In contrast, a large majority of this group--including nearly all those with Native American, African and Asian Y-chromosomes--had mtDNA of indigenous origin. Among men with Eurasian Y-chromosomes, 13 percent had mtDNA from sub-Saharan Africa and only a very few had European mtDNA.
In the 16th century, during its conquest of South America, the Spanish Empire forced countless Incas to work extracting silver from the mountaintop mines of Potosí, in what is now Bolivia--then the largest source of silver in the world. The Inca already knew how to refine silver, but in 1572 the Spanish introduced a new technology that boosted production many times over and sent thick clouds of lead dust rising over the Andes for the first time in history.
Winds carried some of that pollution 500 miles northwest into Peru, where tiny remnants of it settled on the Quelccaya Ice Cap.
There it stayed--buried under hundreds of years of snow and ice--until researchers from The Ohio State University found it in 2003.
In the early online edition of the Proceedings of the National Academy of Sciences, they report discovery of a layer within a Quelccaya ice core that dates to the Spanish conquest of the Inca, contains bits of lead and bears the chemical signature of the silver mines of Potosí.
The core provides the first detailed record of widespread human-produced air pollution in South America from before the industrial revolution, and makes Quelccaya one of only a few select sites on the planet where the pre-industrial human impact on air quality can be studied today.
"This evidence supports the idea that human impact on the environment was widespread even before the industrial revolution," said Paolo Gabrielli, a research scientist at the Byrd Polar and Climate Research Center at Ohio State and corresponding author of the study.
Lonnie Thompson, Distinguished University Professor of earth sciences at Ohio State and co-author of the study, called the find "another keyhole into the past of human activity in that part of the world," and suggested that further investigation could ultimately help us better understand the fate of pollution circulating in the atmosphere today.
Previously, Thompson has called the Quelccaya ice cores a "Rosetta Stone" for gauging Earth's climate history. The samples were cut from ice that formed over 1,200 years as snow settled on the Peruvian Andes. Layer by layer, the ice captured chemicals from the air and precipitation during wet and dry seasons for all those years. Today, researchers analyze the chemistry of different layers to measure historical changes in climate.
For this study, the researchers used a mass spectrometer to measure the amount and type of chemicals present in the ice dating back to 800 AD. They looked for antimony, arsenic, bismuth, molybdenum and especially lead. That's because the refining process that the Spanish introduced to South America involved grinding silver ore--which contains much more lead than silver--into powder before mixing it with mercury in a process called amalgamation. So atmospheric pollution from silver production would chiefly contain traces of lead particulates.
The mass spectrometer revealed some spikes in the concentrations of these elements in the years before Spanish rule, but those layers all likely coincide with natural contamination sources, such as volcanic eruptions. Starting just before 1600, however, the Quelccaya ice began capturing much larger quantities of these elements, and the high amounts persisted until the early 1800s, when South American countries declared independence from Spain.
The remains of the earliest European fort in the interior of what is now the United States have been discovered by a team of archaeologists, providing new insight into the start of the U.S. colonial era and the all-too-human reasons spoiling Spanish dreams of gold and glory.
Spanish Captain Juan Pardo and his men built Fort San Juan in the foothills of the Appalachian Mountains in 1567, nearly 20 years before Sir Walter Raleigh's "lost colony" at Roanoke and 40 years before the Jamestown settlement established England's presence in the region.
Fort San Juan and six others that together stretched from coastal South Carolina into eastern Tennessee were occupied for less than 18 months before the Native Americans destroyed them, killing all but one of the Spanish soldiers who manned the garrisons," said University of Michigan archaeologist Robin Beck.
Beck, an assistant professor in the U-M Department of Anthropology and assistant curator at the U-M Museum of Anthropology, is working with archaeologists Christopher Rodning of Tulane University and David Moore of Warren Wilson College to excavate the site near the city of Morganton in western North Carolina, nearly 300 miles from the Atlantic Coast.
