Linkage Relations of the Genes Histocompatibility-2 and Fused Tail, Brachyury and Kinky Tail in the Mouse, as Determined by Tumor Transplantation.

HE literature on the genetic and antigenic basis of tumor transplantation has T been reviewed by BITTNER (1935), LITTLE (1941; 1947), HAUSCHKA, (1952) and SNELL (1953b, c). In mice, the genetic loci involved were named “histocompatibility” loci by SNELL (1948), the prefix “histo” being used to denote the probable similarity of genes determining reactions to neoplastic and normal tissue transplants. One of these histocompatibility loci, H-2, was shown to be closely linked to the Fu locus by GORER, LYMAN and SNELL (1948). H-2 was shown to be identical with that gene determining antigen I1 present in A strain erythrocytes, which GORER had previously demonstrated (1936, 1937). In addition to H-2 and fused tail (Fu), one or two other loci have been identified on the ninth chromosome in mice: kinky tail (Ki or FuKi) and brachyury (T) . Fused tail is a dominant mutation, viable in the homozygous condition on certain genetic backgrounds, and characterized by the production of kinks and twists in the tail. Penetrance of Fu in heterozygous animals is incomplete with “normal overlaps” being found, the frequency of which varies with the genetic background and sex of the fused parent. The frequency of overlapping is greater when the female introduces the Fu gene than when the male introduces it. Kinky tail (Ki or FuKi) is phenotypically similar to fused tail and may be an allele a t the Fu locus (DUNN and GLUECKSOHN-WAELSCH 1934). Unlike fused, the homozygote is never viable, and there does not appear to be a sex difference in production of normal overlaps, but genetic background may considerably alter its expressian. Hereafter, the gene symbol Ki will be used in referring to kinky. Brachyury ( T ) is a dominant mutation, lethal in homozygous condition. Typically, it produces a shortened tail but is highly variable in expression depending upon genetic background. I t may produce kinks or, on certain genetic backgrounds, tailless animals, or, on still other backgrounds, normal overlaps (ALLEN and SNELL unpublished). For additional details 01 the original references pertaining to the tail mutants described, see GRUN~BERG (1952). Fu, Ki and T are closely linked loci contained within a chromosomal segment of approximately 8 units (DUNN and CASPARI 1945). The order of the loci was uncertain but their evidence pointed to the most probable order as either (1) Ki T Fa