# Mitochondrial Phylogeography of Wild Boars, Sus scrofa, from Asia Minor: Endemic Lineages, Natural Immigration, Historical Anthropogenic Translocations, and Possible Introgression of Domestic Pigs

## TL;DR

This study explores the genetic history of wild boars in Türkiye, revealing native and introduced lineages, and how human activity and geography shaped their distribution.

## Contribution

The study identifies European mitochondrial lineages in Anatolian wild boars, suggesting historical human translocations and introgression.

## Key findings

- Anatolian wild boars contain both native and European (E1) mitochondrial lineages.
- The Bosphorus/Sea of Marmara/Dardanelles acts as a current barrier to female gene flow.
- Historical human activities, including medieval translocations, likely introduced European pigs to Anatolia.

## Abstract

Wild boars from the Middle East, particularly from northern Mesopotamia, formed the original basis of pig domestication at the end of the late Pleistocene. Later, in archaic times, during the classical Greek and Roman periods and the time of the Christian crusaders, wild boars or pigs of European origin were imported and may have interbred with local wild boars, with possible effects on phenotypes and genetic variants in wild boars in Anatolia. We studied the spatial distribution of maternally inherited (mitochondrial) DNA lineages of wild boars from Türkiye to determine whether only natural lineages are present or also lineages indicating historical introductions of pigs or wild boars specifically from Europe. We found native lineages and ones with wider distribution in the Middle East, but also (modern) pig lineages, suggesting prehistoric and/or historical introductions by humans. Our results also showed that the Bosphorus/Sea of Marmara/Dardanelles waterway between northwestern Anatolia and the southeastern Balkans currently represents an effective barrier to natural gene flow in wild boars, at least for females. Apparently, no relevant (maternal) gene flow occurred in the past, when a natural land bridge connected Anatolia with Southeast Europe. The Anatolian lineages are evolutionarily closely linked to other lineages from the Middle East, without a significant evolutionary gap.

Türkiye represents an important biogeographic region connecting Southeast Europe with Southwest Asia, where pig domestication began in the western Palearctic. We studied the phylogenetic relationships and spatial distribution of new and published mitochondrial D-loop sequences of wild boars from Türkiye, other parts of the Middle East, and from around the world to understand migration patterns within Asia Minor and other parts of the Middle East as well as across the Bosphorus/Sea of Marmara/Dardanelles, a current migration barrier to Southwest Europe. Our phylogenetic (ML, BI) and spatial (Geneland) analyses revealed haplotypes both endemic to Anatolia and with a wider distribution in the Middle East as well as European (E1) lineages. The latter suggested possible rare immigration into Anatolia at present times and prehistorical/historical anthropogenic translocations of wild boars or pigs, such as during the pre-Hellenic, Roman, and Byzantine periods or during the European crusades, and subsequent introgression into Anatolian wild boars. Import of pigs with E1 haplotypes and introgression into wild boars during the medieval Empire of Trebizond particularly by Italian merchants or settlers, is also suggested. Anatolian lineages that may have formed the basis of the archaic domestication process of pigs in the western Palearctic are discussed.