Parsimonious Estimation of Sex-Specific Map
Distances by Stepwise Maximum Likelihood Regression
Cathy S.J. Fann and Jurg Ott
Genomics , 29, 571--575 (1995)
Abstract
In human genetic maps, differences between female (x_f)
and male (x_m) map distances may be characterized by
the ratio, R=x_f/x_m, or the relative difference,
Q= (x_f-x_m)/(x_f+x_m) = (R-1)/(R+1). For a map
of genetic markers spread along a chromosome, Q(d)
may be viewed as a graph of Q versus the midpoints,
d, of the map intervals. To estimate male and female
map distances for each interval, a noval method is
proposed to evaluate the most parsimonious trend
of Q(d) along the chromosome, where Q(d) is
expressed as a polynomail in d. Stepwise maximum
likelihood polunomial regression of Q is described.
The procedure has been implemented in a FORTRAN
program package, TREND, and is applied to data on
chromosome 18.
