The jaguar, Panthera onca, is a large cat that lives mainly in South America. The majority of jaguars have light brown fur with black spots, as shown in [Figure 1.1]. Some jaguars have completely black fur, as shown in [Figure 1.2]. (a) The pigments involved in fur colour are produced as a result of biochemical pathways that take place in cells called melanocytes. These pathways are similar to those that occur in human melanocytes. The melanocortin 1 receptor (MC1R) is located on the cell surface membrane of melanocytes and is coded for by the MC1R gene. [Figure 1.3] outlines the processes that occur in jaguar melanocytes.