HAIRPIN-TAIL: A CASE OF POST-REDUCTIONAL GENE ACTION IN THE MOUSE EGG?

Abstract

ABSTRACT Hairpin-tail (Thp) is a new allele of brachyury on chromosome 17 (linkage group IX) of the mouse. The morphological effects in the heterozygote are on the notochord and the tail. The homozygous abnormal is unknown. Thp is unique in that the phenotype of the heterozygote seems to depend on the source of the Thp gene. If it is inherited via the egg the phenotype is extreme and death follows in utero. Embryos derived from a Thp sperm and a+egg are less abnormal and viable. This is not a simple maternal effect, as Thp×Thp matings produce two distinct types of heterozygous embryos.