Genetic studies of the Syrian hamster I. The mutant genes cream, ruby-eye and piebald

Summary

Three mutations in the Syrian hamster are described (cream, ruby-eye and piebald) and the six possible comparisons between the three mutants and sex have been studied for genetic linkage. No evidence for linkage could be found for five comparisons. The sixth comparison (ruby-eye-piebald) exhibited an aberrant segregation which could result from autosomal linkage or from an inviability interaction between the two mutants concerned. Two mutants (ruby-eye, piebald) display significant prenatal inviability and an attempt has been made to elucidate the nature of the prenatal loss. The hypothesis is discussed that the inviabilities observed are a consequence of an inter-dependence between “normal” foetal atrophy and the expected Mendelian proportion of susceptible phenotypes. Since hamster genetics is in its infancy—a plea is made for the publication of all segregation data (negative or otherwise), which can be collated biometrically at a later date.

I am indebted to Mr. G. T. C. Gore for kindly recording the data which constitute cross III and to Miss H. M. Bruce for permission to cite unpublished observations on the onset of sterility in the ruby-eye male. My thanks are due to Mr. N. T. J. Bailey for commenting upon certain aspects of scoring data by the method of maximum likelihood and to Dr. H. M. Quenouille for advice on analysis of variance with non-orthogonal data. I am grateful to Mr. J. A. Sones for much critical discussion.