Ancient Teeth Reveal How Early Americans Survived the Ice Age: Breastfeeding Saved Them
A new study published in the journal Proceedings of the National Academy of Sciences of the United States of America. It shows that a genetic mutation has helped American ancestors survive during the last ice age. The study is called ‘Environmental selection during the last ice age on the mother-to-infant transmission of vitamin D and fatty acids through breast milk’, and it was published on 23 April.
The genetic mutation is common to North Americans and East Asians and, according to Science Magazine, it’s related to Vitamin D intake and breastfeeding.
The early Native Americans settled on the land between Asia and Alaska – which is now under the water. The place is called Beringia.
Researchers at the University of California, Berkeley wrote on the gene called EDAR. They have discovered how Asians and Native Americans from the Ice Age could adapt to survive the long winters at the end of the ice age.
There was little sunlight up in the far north. Sunlight is very important for the production of vitamin D, which helps regulate fat and absorption of calcium. Without enough vitamin D, ancient tribes would have had a lot of health issues. But they hunted large animals and ate a lot of fat to help them survive.
But when it comes to babies, they relied only on milk. The EDAR gene has a variant called V370A, which is an evolved gene that passes more fat and vitamin D from the mother to the baby.
Important Relationship Between Mother and Infant
Study author and biological anthropologist from UC Berkeley, Leslea Hlusko stated in a news release:
“This highlights the importance of the mother-infant relationship and how essential it has been for human survival.”
The evolving gene variant – EDAR V370A was so beneficial, that it spread throughout the entire population in the Americas.
The team of researchers has found out about the gene by looking at the shape of teeth found by archaeologists. After analyzing all 3.183 Native American fossils, they saw all had shoveled teeth, carrying the EDAR V370A variant. They studies teeth of 5,000 skulls from 54 archaeological sites in Europe, Asia, and North and South America. They also saw that 40% of the Asian fossils also had incisors shaped like shovels.
The news release on the study said that “the gene controlling mammary duct growth also affects the shape of human incisors,” making them have a shoveled form.
Early Native Americans have spread the gene to other populations after their arrival, explaining the connection between the genetic trait shared by Native Americans and Asians that live in the north-east regions.
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