The samples are derived from a wide range of ancient populations, rather than a few individuals, and they supplied researchers with five specific genes associated with skin color and diet.
AAAS reports that the “modern humans who came out of Africa to originally settle Europe about 40,000 years are presumed to have had dark skin, which is advantageous in sunny latitudes. And the new data confirm that about 8500 years ago, early hunter-gatherers in Spain, Luxembourg, and Hungary also had darker skin: They lacked versions of two genes—SLC24A5 and SLC45A2—that lead to depigmentation and, therefore, pale skin in Europeans today. […]
Then, the first farmers from the Near East arrived in Europe; they carried both genes for light skin. As they interbred with the indigenous hunter-gatherers, one of their light-skin genes swept through Europe, so that central and southern Europeans also began to have lighter skin. The other gene variant, SLC45A2, was at low levels until about 5800 years ago when it swept up to high frequency.”
This differed from the situation farther north. Ancient remains from southern Sweden 7,700 years ago were found to have the gene variants indicating light skin and blonde hair, and another gene, HERC2/OCA2, which causes blue eyes. This indicated to researchers that ancient hunter-gatherers of northern Europe were already pale and blue-eyed. This light skin trait would have been advantageous in the regions of less sunlight.