Tortoise shell cats can be explained as the offspring from a incomplete dominance cross. Incomplete dominance gives rise to an intermediate phenotype.
The scientific phenomenon that explains the color pattern is X-linked incomplete dominance.
As stated earlier, the tortoise shell colour is as a result of incomplete dominance but as it exists only in females, the inheritance is X linked.
This means the tortoise shell colour is inherited in the heterozygous condition as females have two X (XX) and males (XY) can only be either of the parent's true breeding genotype.
