The ability of rotated ipsilateral grafts of larval hind limb buds on the induction of supernumeraries has been investigated in the tadpoles of Bufo regularis. The distal half of the hind limb bud was grafted ipsilaterally with increments of 45Ëš of clockwise rotation of both the anteroposterior (A-P) and dorsoventral (D-V) axes. The results showed that, the incidence of supernumerary limb formation depends on the degree of angle rotation. The frequency of supernumerary limb production has increased steadily with increasing the angles to reach their maximum values between 180° and 270° inclusively. This increase was relatively enhanced with high incidences of double supernumerary limb formation rather than singles. Nearly all of the supernumeraries have been displaced distally far away from the level of grafting. Small positional discrepancies between graft and stump axes (i.e. after 45° and 315° rotation) gave different results, since supernumerary limb production was comparatively high after 315° rotation (= 78%),and none of these extra-outgrowths has been formed after 45°. The results have been discussed in view of the current theories of pattern formation that rely on the studies of molecular biology. The position of supernumerary outgrowths also suggests that there is no consistent relationship between the emergent site of supernumeraries and the angle of rotation. The present results doesn't hold true with the polar co-ordinate model of French et al. (1976).
Supernumerary limbs – axes disalignment – Ipsilateral rotation – transplantation – hind limbs – anurans