Blue eyes and fair skin
The scientists found that these individuals shared genetic features with people from the north, and those similar genes were absent in farmers who lived in the southern Levant earlier. For example, the allele (one of two or more alternative forms of a gene) that is responsible for blue eyes was associated with 49 percent of the sampled remains, suggesting that blue eyes had become common in people living in Upper Galilee. Another allele hinted that fair skin may have been widespread in the local population as well, the study authors wrote.

"Both eye and skin color are traits that are controlled by complex interactions between multiple alleles, many but not all of which have been identified," Harney explained.

"The two alleles that we highlight in our study are known to be strongly associated with light eye and skin color, respectively, and are often used to make predictions about the appearance of various human populations in ancient DNA studies," she said.

However, it is important to note that multiple other alleles can influence the color of eyes and skin in individuals, Harney added, so "scientists cannot perfectly predict pigmentation in an individual."

The scientists also discovered that genetic diversity increased within groups over time, while genetic differences between groups decreased; this is a pattern that typically emerges in populations after a period of human migration, according to the researchers.