Evidence of hybridisation between the common Indonesian banded pig (Sus scrofa vitattus) and the endangered Java warty pig (Sus verrucosus)

Due to hybridisation and breakdown of reproduction barriers the Java warty pig an endangered suid endemic to Java, may be assimilated into the gene pools of the more common Indonesian banded pig and become extinct. Here, we aimed to detect introgressive hybridisation between both suids by microsatellite genotyping warty pigs from two captive populations and from the wild, as well as a banded pig population. While all but one captive individual were genetically pure, we showed, in contrast to a previous survey based on skull measurements, that five wild-born warty pigs in West Java were hybrids. Moreover, we detected four F2 hybrids in the wild warty pig population (q(range)0.15-0.99) and one F2 hybrid in the wild banded pig population (q = 0.25), confirming reproductive fertility for F1 hybrids. Our results highlight the potential risk of extinction through hybridization and genetic swamping of the endangered warty pig.