Fig. 6From: Landscape genomics: natural selection drives the evolution of mitogenome in penguinsSignificant negative selection for the codons of 13 mtDNA genes using SLAC and FEL methods. Dark cells: SLAC analysis. Empty cells: FEL analysis. ND6 is transcribed from the light strand. Each star represents codons under significant positive selection as determined by SLAC (yellow star) and FEL (orange star) in ND4 and ATP8Back to article page