TSPAN8 and obesity due to melanocortin 4 receptor deficiency: The commonest genes between the three comparisons are TSPAN8, RXFP2, and RIN2. The TSPAN8 (Tetraspanin 8) occurred in the candidate region on Oar3; it is among the genes that are reported to be associated with insulin release and sensitivity, and obesity in humans (Grarup et al., 2008), while the relaxin family peptide receptor 2 (RXFP2) has been associated with horn morphology (Johnston et al., 2011; Wiedemar and Drögemüller, 2015).