Black-spotted Piglets (IMAGE) Uppsala University Caption Black-spotted piglets from the Swedish Linderod breed. The black-spots are caused by the combined effect of two consecutive mutations in the MC1R gene. Credit Photo: Paul Seugling. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.