Question

The offspring of two creeper chicken are

• A. All creepers
• B. Both homozygous and heterozygous creepers
• C. Creepers and normal in the ratio of 3 : 1
• D. Creepers and normal in the ratio of 2 : 1.

Answer 1

Answer: (D)

Creepers and normal in the ratio of 2 : 1.

A gene, when it is homozygous condition, causes death of the organisms, are called Lethal genes. eg: creeper chicken. Creeper is a dominant gene, heterozygous chickens display the creeper phenotype. If two creeper chickens are crossed, one would expect to have (from mendelian genetics) 3/4 of the offspring to be creeper and 1/4 to be normal. Instead the ratio obtained is 2/3 creeper and 1/3 normal. This occurs because homozygous creeper chickens die.

So, the correct option is ‘creepers and normal in the ratio of 2:1’