Gaunitz et al. (1) recently affirmed in the journal Science that the Przewalski’s horse is a feral horse descending from the ancient population of domestic horses of Botai (5,500 BP – North Kazakhstan), and not a truly wild horse. The degree of domesticity of the Botai horses established from archeological artefacts is however questioned (2, 3):
-          The high density of bones supposed to prove husbandry can be explained by an important hunting pressure along a migratory road
-          The diameter of forelegs bones supposed to demonstrate a mount adaptation can be due to environmental variations
-         The handful of observations of tooth wear suggesting harnessing can be due to jewellery craftship (tooth wear is in addition absent from artefacts left by subsequent ancient peoples that were undoubtedly horsemen)
-          The isotope pattern in potsherds supposed to demonstrate milking received methodological criticisms.
In addition the article does not demonstrate that the Przewalski’s horse went through the selective breeding process inherent to domestication (4, 5), and the set of domestic genes typical of domestication not been found so far in the Przewalski’s horse (6). Moreover the Przewalski’s horse has an erected mane which distinguishes it from its domestic counterpart (7).
We therefore contend that the current state knowledge does not justify reclassifying the Przewalski’s horse as a domestic horse.

References
1.            C. Gaunitz et al., Ancient genomes revisit the ancestry of domestic and Przewalski’s horses. Science, eaao3297 (2018).
2.            P. Kosintsev, P. Kuznetsov, COMMENT ON “THE EARLIEST HORSE HARNESSING AND MILKING.” Tyragetia. 7 (2013).
3.            M. A. Levine, Domestication and early history of the horse. The domestic horse: the origins, development and management of its behaviour, 5–22 (2005).
4.            J. Diamond, Evolution, consequences and future of plant and animal domestication. Nature. 418, 700–707 (2002).
5.            G. Larson et al., Current perspectives and the future of domestication studies. Proceedings of the National Academy of Sciences. 111, 6139–6146 (2014).
6.            M. Schubert et al., Prehistoric genomes reveal the genetic foundation and cost of horse domestication. Proceedings of the National Academy of Sciences. 111, E5661–E5669 (2014).
7.            L. Boyd, K. Houpt, in Przewalski’s horse: the history and biology of an endangered species (Lee Boyd and Katherine A. Houpt, Albany, State University of New York Press., 1994).