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New York Daily News
Puerto Rican Gene Pool Runs Deep
November 4, 2003
Everybody knows that Puerto Ricans are the largest ethnic group among the city's 2.2 million Hispanics.
But many of us have been confused for years about how to classify Puerto Ricans or other Hispanics racially.
In the 2000 census, for example, 48% of Hispanics, including Puerto Ricans, identified themselves as "other" racially, followed by "white" (36%), "black" (8%) and "two or more races" (8%).
Less than 1% identified themselves as Indian or Asian. Now along comes a new DNA study that shatters all the traditional views of Puerto Rican racial makeup.
At least 61% of Puerto Ricans possess the same DNA as Indians who inhabited that Caribbean island before the arrival of Columbus, says Prof. Juan Martinez Cruzado, a geneticist at the University of Puerto Rico at Mayaguez.
This is an astounding discovery. For centuries, historians have claimed that Puerto Rico's 50,000 Taino Indians all but disappeared through massacres, disease or overwork within 50 years of the Spanish conquest.
But that was before the Arecibo skeletons were found.
In 1980, a construction crew erecting a boardwalk in the northwestern coastal town of Arecibo unearthed the skeletons of four Indians. The remains eventually were donated to Prof. Martinez Cruzado. Carbon testing revealed they dated from A.D. 645, making them ancestors of the Tainos.
In 1999, Martinez Cruzado got a grant from the National Science Foundation to compare the DNA of the skeletons with that of modern Puerto Ricans. Since then, his team has taken samples from a scientific cross-section of 800 people throughout the island.
Initially Martinez Cruzado analyzed mitochondrial DNA - a genetic marker that can be used to trace heredity through female ancestors.
The research, tabulated only during the past few months, revealed that 61% of the sample had the same DNA as the four Indian skeletons. In addition, 27% had the DNA of Africans, while only 12% had the DNA of white Europeans.
"This challenges the traditional view that Indians in Puerto Rico became extinct in the early 16th century," Martinez Cruzado said in a phone interview yesterday.
"Rather, it suggests there were Indian groups that established themselves at the margins of colonial society and they eventually became assimilated into it."
The mitochondrial study, the professor points out, only shows what genetic material was passed on from mothers to children, not the impact of any male genes on future generations. For that, he had to examine the Y chromosomes - the genetic markers for male heredity - of Puerto Ricans.
"Our samples for the Y chromosome were almost exactly reversed," he said.
About 70% of the Y chromosomes in his 800 samples showed European traits, 20% African and 10% Indian.
According to the professor, the European dominance among male genes makes perfect sense. Most of the early European settlers in Puerto Rico were men, and many intermarried or had children with Indian women, and later with female African slaves.
The fact that so many Puerto Ricans have both Amerindian and European DNA, and that more than 20% possess African DNA, "suggests a greater racial mix" than anyone previously imagined, Martinez Cruzado said.