Thank you for the suggestions to my question about programs demonstrating artificial selection. Several people have asked me to share the responses I received. Henry Schaffer has written some programs: http://www.cals.ncsu.edu/gn/ex/mit-eve.html - With Full Genetic construction of each offspring - With Emphasis on the pattern of heterozygosity over generations and also one for full sib lines Inbreeding - Full Sib Lines Another recommendation was the Populus software developed by Don Alstad and colleagues at the University of Minnesota particularly suitable for Biology Undergrads or have background in Biology. Also suggested was net logo. Rebecca Gray