Estimates of the Sex Ratio of Mutation Rates in Sex‐linked Conditions by the Method of Maximum Likelihood

Summary The method of maximum likelihood is used to provide estimates of the ratio of the mutation rate in females and males, for a sex‐linked recessive trait, Duchenne type muscular dystrophy on three surveys from the literature. One of the estimates (from the Northumberland and Durham data) appears to be significantly lower than the other two. There is a corresponding deficit of single affected fraternities in this survey on the assumption that a detectable mutation rate exists. The combined estimate for Northern Ireland and Utah, x = 0.3506 ± 0.1110, is taken as the best available estimate. This leads to a sex ratio ( μ/v ) of 1.1734 which is consistent with equal mutation rates.