Press release on the scientific discovery: https://www.inrae.fr/en/news/mystery-four-horned-goats-and-sheep-finally-solved

Their results reveal that polycerate individuals all carry a mutation affecting the same gene: HOXD1. This is a homeotic gene, which means that it is involved in the organisation of the body plan during the development of embryos.

I hope no mad scientist ever plays with that gene 😅

Article of the photo source https://myanmarnewsfeed.xyz/la-oveja-hebridean-de-cuatro-cuernos-una-criatura-iconica-y-misteriosa/