Class 12 NEET Biology Principles of Inheritance and Variation Questions Part 1

It is a sex-linked disease. It is a disease which occurs due to gene responsible for determining the character concerned and is carried on a sex chromosome. In humans, this is always X-chromosome e.g. colourblindness. Here a genetically diseased father (male) marries with a normal female (homozygous). Colour blindness is recessive to normal vision so that the sons produced would be normal, but daughters will be heterozygous (normal phenotype), which means that these daughters will be carriers of this trait