[Temperature-sensitive mutations as a possible cause of human embryo fatalities]

Mutations to temperature sensitivity (ts') are suggested to be a casue of the embryo death. In the course of investigation of 102 cases of spontaneous abortions (sporadic and habitual) in 5 cases it was found, that cells propagate badly at 37 degrees C and die at 40 degrees C. Such cell strains could be successfully maintained only at 32 degrees C. Thus the possibility of direct identification of human embryolethals is proved. A hypothesis is advanced that ts' mutations can be a cause not only of spontaneous abortions, but of congenital malformations as well.