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/
Yeah, it is pretty nightmare fuelish, but the advances in developmental biology that came from those studies was amazing. Interesting how the formation of different organisms can follow very similar processes.