Background and Aim: The Samosir goat has a high cultural value and is a source of germplasm in Indonesia. This study aimed to reveal the history and selection signatures of the Samosir goat.

Materials and Methods: A total of 25 goats were divided into seven subpopulations of Indonesian goat breeds. Deoxyribonucleic acid (DNA) from blood samples was isolated with the use of the gSYNC™ DNA Mini Kit (Geneaid, Taipei, Taiwan). Cytb gene amplification was performed by the polymerase chain reaction (PCR) method, and the PCR products were sequenced. A phylogenetic tree was constructed by the neighbor-joining method using MEGA 11 software. A questionnaire was used to collect information related to the history and breeding practices of the Samosir goat on Samosir Island.

Results: Samosir goats are divided into four groups based on their coat color: Completely white, white with brown spots, white with black spots, and white with brown and black spots. The body form of the Samosir goat is similar to that of the Kacang goat. The space below a traditional Toba Batak house is used as a goat pen. The genetic difference between the Samosir goat and the Kacang goat based on the Cytb gene was approximately 0.1%.

Conclusion: Phylogenetic analysis between Samosir goats and other indigenous Indonesian goats revealed that Samosir goats form a single clade, with a very close genetic distance from other local goats, such as the Kacang goat. The Toba Batak culture on Samosir Island has significantly influenced the selection and formation of the Samosir goat breed.

Keywords: Batak tribe, ethnobiology, mitochondrial DNA, phylogenetic analysis, Samosir goat.