Abstract
Population genomic studies of ancient human remains have
shown how modern-day European population structure has been
shaped by a number of prehistoric migrations. The Neolithization
of Europe has been associated with large-scale migrations from
Anatolia, which was followed by migrations of herders from the
Pontic steppe at the onset of the Bronze Age. Southwestern
Europe was one of the last parts of the continent reached by these
migrations, and modern-day populations from this region show
intriguing similarities to the initial Neolithic migrants. Partly due to
climatic conditions that are unfavorable for DNA preservation,
regional studies on the Mediterranean remain challenging. Here,
we present genome-wide sequence data from 13 individuals
combined with stable isotope analysis from the north and south
of Iberia covering a four-millennial temporal transect (7,500–3,500
BP). Early Iberian farmers and Early Central European farmers exhibit
significant genetic differences, suggesting two independent
fronts of the Neolithic expansion. The first Neolithic migrants that
arrived in Iberia had low levels of genetic diversity, potentially
reflecting a small number of individuals; this diversity gradually
increased over time from mixing with local hunter-gatherers and
potential population expansion. The impact of post-Neolithic migrations
on Iberia was much smaller than for the rest of the continent,
showing little external influence from the Neolithic to the
Bronze Age. Paleodietary reconstruction shows that these populations
have a remarkable degree of dietary homogeneity across
space and time, suggesting a strong reliance on terrestrial food
resources despite changing culture and genetic make-up.