In the Mexican salamander (Ambystoma mexicanum) homozygous for the geneeyeless, unilateral neural fold rearrangements stimulate bilateral eye formation

✍ Scribed by Brun, Rudolf B.

• Book ID: 102893033
• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 706 KB
• Volume: 254
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402540115

✦ Synopsis

Abstract

The objective of the present investigation was to test the hypothesis that the absence of eyes in the eyeless mutant Mexican salamander (Ambystoma mexicanum) might be caused by an antero‐posterior morphogenetic system out of balance in the head of the mutant. To test this hypothesis the antero‐posterior sequence of the neural fold of eyeless mutant neurulae was rearranged in two ways: unilateral grafting of posterior neural fold tissues from mutant donors into the anterior nasal area of mutant hosts (and vice‐versa) was performed; and in addition, the eye region of the mutant was moved into posterior temporal positions as well as shifted forward into the nasal area. The results of these experiments demonstrate that larvae homozygous for the eyeless mutant gene are capable of forming eyes in vivo following such antero‐posterior rearrangements of their neural folds. In addition, operations performed unilaterally had a bilateral effect: eye structures differentiated on the operated as well as on the unoperated side of the larvae. These results suggest that the eyeless mutant fails to form eyes because of an inhibitory effect on the optic vesicles emanating from neighboring tissues, not because of an inherent defect in the neural plate to form retina.