Regarding to the QTL on chromosome 4, Rikimaru et al. (2013) [29] assumed that cholecystokinin type A receptor (CCKAR) is a candidate gene for growth traits because it was located just under the QTL peak on chromosome 4 and has also been identified as a candidate gene for human obesity [30]. Here, CCKAR is linked to obesity due to melanocortin 4 receptor deficiency.