Among lion, tiger and a domestic cat, all the three have the same number of 38 chromosomes, yet they have different appearances. How do you account for such differences?

Although lion, tiger and domestic cat have the same number of chromosomes i.e., 38 chromosomes but they have different physical appearance because the characteristics of species including physical appearance, body functions, etc., are not depend on the number of the chromosome but these are the results of genes which are located on chromosomes.