For a human blood, there are two alleles (called S and s) and three distinct phenotypes that can be identified by means of the appropriate reagents. The following data was taken from people in Britain. Among the 1000 people sampled, the following genotype frequencies were observed SS = 99, Ss […]

1.     Assume you are studying fruit fly wing development. The wingless gene determines the shape of wings. The phenotype associated with the dominant allele, W, is normal wing development. The phenotype associated with the recessive allele, w, is a wing with notches. You cross a true breeding fly having normal wings with a […]

Water snakes are common in the area around Lake Erie. They live on the mainland as well as islands in the lake. The island and mainland populations are relatively isolated, but migration does occur. Interestingly, selection favors banded water snakes on the mainland and unbanded on the islands. Bandedness is […]

Based on human logic, if a parasite kills it’s host it is also harming itself. Tapeworms then appear to be “perfect parasites” because they cause very few symptoms in the host and are therefore able to shed eggs at will. But, diseases like antibiotic-resistant tuberculosis or viral cancers do kill […]