Experimental studies on a new lethal trait in Mexican axolotls of the Wistar Institute white strain

✍ Scribed by Humphrey, R. R.

• Publisher: John Wiley and Sons
• Year: 1973
• Tongue: English
• Weight: 667 KB
• Volume: 183
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1401830208

✦ Synopsis

Abstract

An additional lethal gene (y) in white Mexican axolotls of the Wistar Institute stock, first discovered in 1965, is believed to have arisen by mutation only two generations earlier. Larvae homozygous for y develop normally for about two weeks after hatching, and become recognizable at that time by the cessation of growth in the forelimbs. Death occurs at the age of five to seven weeks.

Experimental studies (transplantation, parabiosis) suggest that gene y deter‐
mines metabolic deficiencies in all cells of the embryo. Forelimb transplants
produce limbs which cease growth and differentiation and persist as short
stumps which, even though partially replaced by host tissues, lack capacity
for normal differentiation or for regeneration after amputation. Transplants
including Wolffian duct and the primordia of gonad and mesonephros produce
non‐functional mesonephric tubules and gonads in which the germ cells
degenerate and disappear. In parabiosis with a normal cotwin a mutant larva
may be kept alive for several months but shows extensive degeneration and
disappearance of muscle fibers, and eventual loss of gastrointestinal epithelium
and glands, gonads, and mesonephros. The growth of the normal cotwin is
greatly inhibited, probably because its vital organs are overburdened as those
of its lethal partner cease to function. Only one pair reached the age of six
months, with the normal member attaining a length of only 25 mm, one‐fourth
or less the length of normal larvae of that age.