dataframe with at least id, dam and sire in columns 1-3,
respectively. If columns with parental LLRs and/or Mendelian errors are
present, these will be plotted as well.
Panels
character vector with panel(s) to plot. Choose from 'all',
'G.parents' (parents of genotyped individuals), 'D.parents' (parents of
dummies), 'O.parents' (parents of non-genotyped non-dummies), sibships',
'LLR', 'OH'.
ask
ask for user key stroke before proceeding to next plot.