However, Harvard geneticist David Reich notes that recent genetic studies have identified patterns that support Greenberg's Amerind classification: the "First American” category. "The cluster of populations that he predicted to be most closely related based on language were in fact verified by the genetic patterns in populations for which data are available.” Nevertheless, this category of "First American" people also interbred with and contributed a significant amount of genes to the ancestors of both Eskimo-Aleut and Na-Dené populations, with 60% and 90% "First American" DNA respectively constituting the genetic makeup of the two groups.Reich, David. (2018). Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past. Chapter 7. New York: Pantheon Books (2018).
However, Harvard geneticist David Reich notes that recent genetic studies have identified patterns that support Greenberg's Amerind classification: the "First American” category "The cluster of populations that he predicted to be most closel.y related based on language were in fact verified by the genetic patterns in populations for which data are available.” Nevertheless, this category of "First American" people also interbred with and contributed a significant amount of genes to the ancestors of both Eskimo-Aleut and Na-Dené populations, with 60% and 90% "First American" DNA respectively constituting the genetic makeup of the two groups.Reich, David. (2018). Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past. Chapter 7. New York: Pantheon Books (2018).