Knobbly, a new dominant mutation in the mouse that affects embryonic ectoderm organization

Abstract

SUMMARYKnobbly,FuKb, a dominant mutation on chromosome 17 of the mouse, causes a kinked tail in heterozygotes and embryonic lethality at about nine days in homozygotes. Abnormal organization of the embryonic ectoderm is first apparent at about embryonic day 7, and the retarded and malformed embryos die by mid 9 days.Kink,FuKi, a dominant gene that maps in the same region, is also an embryonic lethal in homozygotes; heterozygotes have kinked tails and often a circling gait. We have shownFuKbandFuKiare allelic; theFuKb/FuKicompound dies at the same time asFuKb/FuKbembryos with the same morphological syndrome.TheFuKbphenotype is not seen in offspring in expected ratios. TheFuKbmales may have a low transmission ratio or penetrance may be incomplete.An incidental finding of our histological studies is a high incidence of complete twinning whenFuKbheterozygotes mateinter seor whenFuKb×FuKimatings are made.