A MAXIMUM-LIKELIHOOD ALGORITHM FOR GENOME MAPPING OF CYTOGENETIC LOCIFROM MEIOTIC CONFIGURATION DATA

Frequencies of meiotic configurations in cytogenetic stocks are depend ent on chiasma frequencies in segments defined by centromeres, breakpo ints, and telomeres, The expectation maximization algorithm is propose d as a general method to perform maximum likelihood estimations of the chiasma frequencies in the intervals between such locations, The esti mates can be translated via mapping functions into genetic maps of cyt ogenetic landmarks. One set of observational data was analyzed to exem plify application of these methods, results of which were largely conc ordant with other comparable data. The method was also tested by Monte Carlo simulation of frequencies of meiotic configurations from a mono telodisomic translocation heterozygote, assuming six different sample sizes, The estimate averages were always close to the values given ini tially to the parameters, The maximum likelihood estimation procedures can be extended readily to other kinds of cytogenetic stocks and allo w the pooling of diverse cytogenetic data to collectively estimate len gths of segments, arms, and chromosomes.