The findings of this research indicate that it is important for teache
rs to be aware of students' concepts in genetics before they start tea
ching them. It also showed that once students had resolved any difficu
lty with the relationship between gene and allele, their performances
in genetics showed a significant improvement. This research found that
the use of a chromosome model as a conceptual challenge tool was a mo
st effective way of resolving these difficulties, especially if teache
rs were aware of students' concepts, and had undergone some staff deve
lopment in the model's use.