Genetic analysis reveals blue eyes evolved before light skin.

SKULL: J.M. VIDAL ENCINA; ILLUSTRATION: CSIC

Skeletal remains from a 7,000 year old Spaniard have been genetically sequenced and suggests that the evolutionary onset of light-colored eyes predates light skin. The results also gave clues to what his diet might have been like. The lead author on the paper was Iñigo Olalde of Barcelona’s Institut de Biologia Evolutiva and it was published in Nature.

The remains were discovered in northwestern Spain at the La Braña-Arintero site. The skeleton belonged to a man from the Mesolithic Period who has been dubbed La Braña 1. One of his teeth yielded enough DNA to complete a genetic analysis. The results gave important clues about the evolution of appearance and diet in the region.

Though the height and approximate age at time of death were not released, the researchers were able to determine that La Braña 1 did not look quite how they expected. His dark hair and dark skin were not unusual, but he likely had light eyes which was very unusual for this time period. The exact shade of his eyes could not be determined, but it was clear to the researchers that they were not brown. This could very well mean that light eyes made their evolutionary debut before light skin.

Fresh baked bread, rice, and cheese are dietary staples in Spain today, though this was not always the case. According to the analysis, he only had a few copies of the genes responsible for breaking down starch. This indicates that the diet was limited in grains and starchy vegetables like potatoes. Though wheat and other grains were already domesticated by this point, they were not common in Europe at this juncture. Once agriculture became more commonplace, it is likely that those who had more copies of genes allowing them to digest starch had an advantage, as they were able to consume this easily obtained food.

La Braña 1’s genome also shows that he was lactose intolerant, meaning he did not consume dairy products. While lactose intolerance is seen as an anomaly in some regions, it is globally and historically the norm. Many people produce the enzyme lactase early in life when they depend on breast milk, but that function decreases over time. Many people are able to produce lactase throughout their entire lives and eat dairy without a problem, but this lactose persistence is actually much more rare.

Another male skeleton, named La Braña 2, was also discovered by the team in 2006. Unfortunately, the DNA was not as well preserved in this second individual, which is making it difficult for the researchers to sequence. They are currently working to restore the genome and provide more information about what the earliest Europeans looked like during the Mesolithic Period.

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