chr
Optional vector indicating the chromosomes to consider.
This should be a vector of character strings referring to chromosomes
by name; numeric values are converted to strings. Refer to
chromosomes with a preceding -
to have all chromosomes but
those considered. A logical (TRUE/FALSE) vector may also be used.
as.table
If TRUE, return the genetic map as a table with
chromosome assignments and marker names. If FALSE, return the map as a
"map"
object.