The Biarzo case in northern Italy: is the temporal dynamic of swine mitochondrial DNA lineages in Europe related to domestication?

Abstract

Genetically-based reconstructions of the history of pig domestication in Europe are based on two major pillars: 1) the temporal changes of mitochondrial DNA lineages are related to domestication; 2) Near Eastern haplotypes which appeared and then disappeared in some sites across Europe are genetic markers of the first Near Eastern domestic pigs. We typed a small but informative fragment of the mitochondrial DNA in 23 Sus scrofa samples from a site in north eastern Italy (Biarzo shelter) which provides a continuous record across a ≈6,000 year time frame from the Upper Palaeolithic to the Neolithic. We additionally carried out several radiocarbon dating. We found that a rapid mitochondrial DNA turnover occurred during the Mesolithic, suggesting that substantial changes in the composition of pig mitochondrial lineages can occur naturally across few millennia independently of domestication processes. Moreover, so-called Near Eastern haplotypes were present here at least two millennia before the arrival of Neolithic package in the same area. Consequently, we recommend a re-evaluation of the previous idea that Neolithic farmers introduced pigs domesticated in the Near East, and that Mesolithic communities acquired domestic pigs via cultural exchanges, to include the possibility of a more parsimonious hypothesis of local domestication in Europe.

Like a pig out of water: seaborne spread of domestic pigs in Southern Italy and Sardinia during the Bronze and Iron Ages

“…This could be either because Y1 individuals were already there but never found before or humans exploiting this particular strain at least during the Bronze Age brought them to the islands. The first scenario is consistent with natural dispersion from other Italian areas (such as it is the case for Biarzo in Northern Italy, where pigs' remains belong to the Y2 haplotype; Vai et al, 2015). However, unlike the Y2 haplotype, which occurs in several pre-Neolithic European contexts (Evin et al, 2015, Vai et al, 2015 and in modern feral pigs from Corsica (Larson et al, 2007), the Y1 haplotype was never found in neither Mesolithic or modern European wild boar.…”

“…The endemic Italian clade has been previously found only in ancient Italian and Croatian specimens (Larson et al, 2007, Vai et al, 2015. Currently, the E2 clade is observed only in Central/Southern Italian wild boar and Sardinian feral populations, but never in domestic pigs (Scandura et al, 2008;Alexandri et al, 2012;Vilac¸a et al, 2014).…”

“…The sequencing of a short mitochondrial D-loop region (80 bp) from ancient pig remains allowed, revealing that early Neolithic farmers introduced domestic pigs into Northern Europe from the Near East by the sixth millennium BC, through the so-called Danubian route. By the Bronze Age (3900 BC), European domestic pigs had replaced the Near Eastern mitochondrial haplotype (more likely through a reciprocal gene flow between local wild populations and introduced domestic stocks) and eventually spread into the Fertile Crescent (Larson et al, 2007;Evin et al, 2015;Vai et al, 2015). Domestication and dispersal of pigs into Europe following the Northern (Danubian) route is thus well documented (Larson et al, 2007;Krause-Kyora et al, 2013).…”

“…The European clade (E1) further shows a geographical partition in two haplogroups: A-side haplotypes are common in Central Europe and Italy, whereas C-side haplotypes are mostly found in Iberia and Eastern Europe (Giuffra et al, 2000;Larson et al, 2005;Scandura et al, 2011;Vilaça et al, 2014;Lega et al, 2016). The Near Eastern clade is traditionally characterized by the Y1 haplotype, endemic to Anatolia, and by the Y2 haplotype, whose geographical origin is currently uncertain (Evin et al, 2015;Vai et al, 2015).…”

The relationship between mitochondrial DNA haplotype and the reproductive capacity of domestic pigs (Sus scrofa domesticus)

“…MtDNA turnover has been studied in the context of pig domestication, which is important to understand how modern human society was shaped by agricultural practice [ 59 – 61 ]. The present paper focuses on the distribution of mtDNA haplotypes amongst commercial pigs that were introduced to Australia.…”