I designed this activity to go with the VGL-1 free genetics software (included in the zip file). It leads students, through scaffolded inquiry, how to perform test crosses to figure out simple inheritance patterns. This is significantly easier and quicker than dealing with real fruit flies! Concepts explored through this include: dominant allele, recessive allele, heterozygous, homozygous, test cross, autosomal dominance, punnett squares. I used this with IB-SL Biology students but would be appropriate for AP Biology or advanced/honors high school biology. The VGL-1 program (.exe) runs on a PC operating system and will run from the .exe file without needing to be installed.