Developmental abnormalities in the head region of the talpid3 mutant of the fowl

The abnormal fowl embryos known as talpids are so called because of their short spade-like wings, which somewhat resemble the fore-limbs of the mole (Talpa). The condition was discovered by Cole (1942), who established that it represented the homozygous expression of an autosomal recessive gene, ta. Abbott, Taylor & Abplanalp (1959) described a mutant broadly resembling Cole's, which they designated talpid2, and which they found to be similarly dependent upon an autosomal recessive gene, ta2. Hunton (1960), examining the dead-in-shell from the Light Sussex flock at Wye College, discovered an inherited abnormality, hereafter referred to as talpid3, closely resembling Cole's mutant and probably having a similar genetic basis, which is the subject of the present investigation. No tests for allelism of the three talpid genes have been made (Cole's talpid is extinct), but it is possible that they are alleles with different grades of expression.