Question

It is known that homozygous dominant gene for a type of cone gives brown colour. The formation of cones with brown, yellow colour expresses the _______________ and white expresses the _______________

(a) Penetrance, expressivity

(b) Expressivity, genotype

(c) Genotype, Phenotype

(d) Expressivity, penetrance

I got this question in an interview for job.

This intriguing question originated from Penetrance and Expressivity topic in chapter Regulating Gene Expression in Eukaryotes of Cytogenetics

Answer 1

The correct option is (d) Expressivity, penetrance

To explain: The formation of coloured cones is sure that the cones are penetrant, it is variation in the expressivity that gives them different colour. The uncoloured cone shows no penetrance.