Pedigree-drawing with R and graphvizGraphical display of pedigree data is of interest in family studies and there are many computer programs avaiable [see Dudbridge et al. (2004) and Author Webpage]. For example, there is a flexible yet sophisticated package under the GNU General Public License (Author Webpage) called Madeline (Author Webpage). In view of the rising interest in R (Zhao and Tan, 2006), two R functions for drawing ped
