Pacific pigs can trace their ancestry to the domesticated pigs of Southeast Asia that accompanied the first Austronesian-speaking groups in their homeland. island-hopping migration across the regionaccording to a new genomic study from the University of Oxford and Queen Mary University of London, both in the United Kingdom.
As stated in ‘Science“For thousands of years, humans have moved animals far beyond their natural range, sometimes accidentally and sometimes deliberately, but often with profound ecological consequencesespecially on the islands.
Pigs are a notable example; Although their range is primarily west of the Wallace Line, several species are now widely distributed on the islands of Southeast Asia and throughout Oceania.
Archaeological and genetic evidence suggests that pigs were brought east more than 4,000 years ago, before the great Austronesian migrations, and that subsequent human expansions took them further across the Pacific. However, studies show that pigs endemic to these regions have a distinctive genetic signature of the “Pacific Clade”‘, shared by wild and free-ranging pigs in other parts of mainland Southeast Asia. This trend raises questions about the precise nature of the origin and dispersal of pig populations in the Pacific, as well as the role of humans in this evolution.
To trace the origins of pigs in Wallacea, Melanesia, Micronesia and Polynesia, researchers sequenced 117 modern, historical and ancient pig genomes spanning the past 2,900 years and analyzed tooth shape data from 401 modern specimens and 313 archaeological specimens. In this way, they discovered that pigs from the Philippines to Hawaii were largely descended from domestic pigs brought by Austronesian-speaking groups from southeastern China and Taiwan around 4,000 years ago.
This pattern reflects early human migrations
In addition, Oceanian pigs do not present genetic mixing with wild pig species native to islands along the migratory route, indicating that the first introduced animals remained genetically isolated from local populations. Only later did isolated wild populations interbreed with endemic wild species.
According to the authors, this trend reflects early and successive human migrations across the region, which also involved limited mixing with local groups, suggesting that these pigs possessed domestic characteristics well suited for transport and reproduction.
Repeated island-to-island movements shaped their evolution through genetic bottlenecks, selective pressures, and subsequent gene flow, which helped explain their success in spreading across the island islands of Southeast Asia and the western Pacific.
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