A new analysis of the shapes of more than 5,000 ancient teeth from a number of hominid species suggests that arrivals from Asia played a greater role in colonizing Europe than hominids direct from Africa. These Asian hominids originated from Africa and, after migrating, had evolved independently.
This blog previously noted that 70 percent of English men, 95 percent of Spanish men, and 95 percent of Irish men have a y chromosome mutation known as M173. Spencer Wells, an American geneticist and anthropologist leading the Genographic project has observed:
“The reason a lot of western Europeans have it is because it defines an expansion in the end of the last ice age as people moved north out of Iberia [ancient Spain]. The cool thing is that the penultimate marker, if you go back one step from M173, is M45, which arose in Central Asia, so it tells you about this journey your ancestors took through the steppes of Central Asia hunting mammoths and so on. Before that they were down in the Middle East.”
National Geographic Magazine reports that a tooth study also suggests that the first Europeans migrated from Asia rather than from Africa.
“Asia was also an important center for hominid speciation,” said Maria Martinón-Torres, a scientist at the National Research Center on Human Evolution in Burgos, Spain, who led the study.
The analysis of the teeth was extensive. The researchers used more than 50 indicators, such as fissure patterns, overall size, and length-to-width ratio. The large data set could be used to establish classes. Since genetic code strongly influences tooth shape, the different classes could be indicative of a migratory pattern.
“We looked at the entire landscape of the teeth — the mountains, valleys, ridges — everything,” Martinón-Torres said.
What they found is that European teeth were more similar to Asian teeth than they were to African teeth.
However, the results don’t rule out African influence on European genes.
“This finding does not necessarily imply that there was not genetic flow between continents,” Martinón-Torres and colleagues write in their paper, “but emphasizes that this interchange could have been both ways.”
Rather than a one-way stream of people coming from Africa, Martinón-Torres and colleagues think there must have been a more fluid pattern of migrations.
“Just because people had come out of Africa didn’t mean that they couldn’t turn around and go back again,” she said.
Erika Hagelberg, a geneticist from the University of Oslo in Norway, is impressed with the study, but cautious about how it should be interpreted.
“The study shows that the genetic impact of Asia on Europe is stronger than that of Africa. But the teeth can’t tell us the direction or the time when people migrated,” she said.