onemap (version 2.0-1)

map: Construct the linkage map for a sequence of markers

Description

Estimates the multipoint log-likelihood, linkage phases and recombination frequencies for a sequence of markers in a given order.

Usage

map(input.seq, tol)

Arguments

input.seq

an object of class sequence.

tol

tolerance for the C routine, i.e., the value used to evaluate convergence.

Value

• An object of class sequence, which is a list containing the following components:
• seq.num
  a vector containing the (ordered) indices of markers in the sequence, according to the input file.
• seq.phases
  a vector with the linkage phases between markers in the sequence, in corresponding positions. -1 means that there are no defined linkage phases.
• seq.rf
  a vector with the recombination frequencies between markers in the sequence. -1 means that there are no estimated recombination frequencies.
• seq.like
  log-likelihood of the corresponding linkage map.
• data.name
  name of the object of class outcross with the raw data.
• twopt
  name of the object of class rf.2pts with the 2-point analyses.

Details

Markers are mapped in the order defined in the object input.seq. If this object also contains a user-defined combination of linkage phases, recombination frequencies and log-likelihood are estimated for that particular case. Otherwise, the best linkage phase combination is also estimated. The multipoint likelihood is calculated according to Wu et al. (2002b)(Eqs. 7a to 11), assuming that the recombination fraction is the same in both parents. Hidden Markov chain codes adapted from Broman et al. (2008) were used.

References

Broman, K. W., Wu, H., Churchill, G., Sen, S., Yandell, B. (2008) qtl: Tools for analyzing QTL experiments R package version 1.09-43 Jiang, C. and Zeng, Z.-B. (1997). Mapping quantitative trait loci with dominant and missing markers in various crosses from two inbred lines. Genetica 101: 47-58.

Lander, E. S., Green, P., Abrahamson, J., Barlow, A., Daly, M. J., Lincoln, S. E. and Newburg, L. (1987) MAPMAKER: An interactive computer package for constructing primary genetic linkage maps of experimental and natural populations. Genomics 1: 174-181. Wu, R., Ma, C.-X., Painter, I. and Zeng, Z.-B. (2002a) Simultaneous maximum likelihood estimation of linkage and linkage phases in outcrossing species. Theoretical Population Biology 61: 349-363. Wu, R., Ma, C.-X., Wu, S. S. and Zeng, Z.-B. (2002b). Linkage mapping of sex-specific differences. Genetical Research 79: 85-96

See Also

make.seq

Examples

data(example.out)
  twopt <- rf.2pts(example.out)

  markers <- make.seq(twopt,c(30,12,3,14,2)) # correct phases
  map(markers)

  markers <- make.seq(twopt,c(30,12,3,14,2),phase=c(4,1,4,3)) # incorrect phases
  map(markers)