Flawed evidence for convergent evolution of the circadian CLOCK gene in mole-rats

Convergently evolved mole-rats (Mammalia, Rodentia) provide a fascinating model for studying convergent molecular evolution. Three genome sequences have recently been made available for the blind mole-rat ( Nannospalax galili ; Spalacidae; Muroidea) 1 , and the convergently evolved naked mole-rat ( Heterocephalus glaber ; Heterocephalidae; Ctenohystrica) 2 and its close relative the Damaraland mole-rat ( Fukomys damarensis ; Bathyergidae; Ctenohystrica) 3 . In their genome paper 1 , Fang et al. evaluated convergent molecular evolution related to the subterranean life-style between the naked mole-rat and the blind mole-rat. One particularly striking result was the strong signal for amino acid convergence detected in the circadian rhythm CLOCK gene. Here I show that this unexpected result is erroneous because it is based on the use of the wrong sequence for the naked mole-rat, which has been mistakenly replaced by a sequence from a blind mole-rat. When the correct sequence is used, the evidence for convergent molecular evolution in this gene appears very limited.