(a)[5]
With suitable symbols, draw a genetic diagram to illustrate the outcome of a cross between a female tortoiseshell cat and a male ginger cat. Your answer should include symbols, parent phenotypes, parent genotypes, gametes, offspring genotypes and offspring phenotypes.
(b)[3]
In humans the $TYR$ gene plays a role in producing a dark pigment, melanin, in some cells. Describe how expression of the $TYR$ gene results in melanin production.