Extended Data Figure 1: Equivalent stages of mouse and bovine fore- and hindlimb development.
From: Attenuated sensing of SHH by Ptch1 underlies evolution of bovine limbs
a, Table listing the developmentally equivalent bovine fore- and hindlimb bud stages in comparison to mouse forelimb buds. CRL, approximate crown-rump length as previously defined49. b, False-coloured CT scan of a bovine fetus (at 5 months of gestation) to detect the ossified skeletal bones. Left limbs were coloured blue and right limbs orange. Radius and ulna form as two distinct skeletal elements, while the metacarpals/metatarsals fuse during ossification to give rise to the cannon bone, a convergent trait in many artiodactyls2. Lower panels illustrate the similarities of the forelimb (FL) and hindlimb (HL) autopod skeletal bones. Arrowheads indicate the plane of fusion of the metacarpal/metatarsal bones. Two independent fetuses were analysed. s, scapula; h, humerus; r, radius; u, ulna; c*, region corresponding to the not yet ossified carpus; cb, cannon bone; p, phalanges. III, IV, digits.
