Counting algorithms for linkage: correction to Morton and Collins

In a recent paper, Morton & Collins (1990) claimed: (1) that the Lander-Green algorithm for genetic linkage analysis is not the EM algorithm for finding the maximum likelihood map; and (2) that a proposed alternative algorithm does have these properties. Here, we show that these assertions are both incorrect: the Lander-Green algorithm is an EM algorithm, while the Morton-Collins algorithm is not. We note that Morton and Collins concur with these conclusions.