Illustrative examples are shown in Figure 7. First, a recently evolved enhancer in naked mole rat is shown upstream of the thymopoietin gene (TMPO), identified previously as positively selected (Kim et al., 2011). The orthologous TMPO regions in human, mouse, cow, and dog show no enhancer activity, though a number of partially conserved enhancers are present nearby (Figure 7A). Second, the genomic region around the TRIP12 gene, under positive selection in dolphin (Sun et al.,2013), contains a recently evolved dolphin enhancer not active in human, mouse, dog, and cow. Moreover, this regulatory element appears to be the main enhancer in this region (Figure 7B).