On the use of the moments method of estimation to obtain approximate maximum likelihood estimates of linkage between a genetic marker and a quantitative locus.

The approximate maximum likelihood method of Luo & Kearsey (1989) to determine the parameters of a segregating quantitative trait locus (QTL) in an F2 population by linkage to a genetic marker is compared to the 'true' maximum likelihood estimates derived by scanning the seven parameter likelihood space. The two methods did not yield identical results, and diverged markedly for a dominant QTL loosely linked to the genetic marker. Further study is suggested to evaluate other methods that do not simultaneously maximize the likelihood for all parameters.