[Commentary] The parasite-mediated domestication hypothesis: on the common cause of known domestication mechanisms

The parasite-mediated domestication hypothesis (PMD) brings a new aspect to the understanding of animal domestication. Basically, the PMD draws from the assumption that the conditions underlying the domestication process in animals (particularly mammals) and thus the domestication syndrome/phenotypes had a common cause, namely parasites (particularly endoparasites – helminths and protozoa). The PMD does not stand in contrast to its predecessors. Neither the fundamental work of Belyaev (fox experiment, destabilising selection) nor that of Wilkins and colleagues (neural crest cells deficits during embryonic development), which both elucidated and explained the developmental mechanisms of the domestication syndrome. PMD goes further and proposes an initial trigger for the modulation of these mechanisms and thus for the developmental changes that then lead to the domestication syndrome. As appeals to explain the underlying mechanisms of PMD have emerged, this commentary will attempt to provide some more clarity on the PMD rationale. In fact, PMD is basically a causal hypothesis and simply states that the known developmental mechanisms leading to domestication syndrome, all of which have been well explained previously, are triggered by parasites (endoparasites in particular).