Can Specific Mutations Be Induced by Serological Methods?

Fu/Fu.) When the posterior axial region is sufficiently defective, it fails to provide the normal inductive stimuli which regulate the development of the posterior gut and urinary ducts, and particularly the separation of the urogenital sinus from the rectum. This assumption is based not on embryological evidence but on the evident connection between abnormalities of the posterior spine and urogenital system. The hypothesis implies that the mutations studied (u, Sd, Ki, T, Fu, t° or t') have some effect in common which underlies the process or processes leading to the abnormal connection between gut and urinary duct. They apparently differ in their effects on certain other processes since each mutant probably has peculiar effects on tail form by which it can be identified. Further study may, of course, reveal differences in the urogenital effects of the different mutants, but the essential features of the syndrome, failure of posterior gut and urinary duct and absence of anus, appear to be the usual type of response of the embryo to anatomical defects brought about by a number of independent mutations.