Question

The normal body colour of a grasshopper is green. The gene for this character is present on X chromosome. Due to recessive mutation in this gene, grasshoppers with pink body colour are produced. A male grasshopper with green body colour mates with a female grasshopper with pink body colour. Which of these statements is true?

• A. All offsprings will be green irrespective of sex.
• B. All offsprings will be pink irrespective of sex.
• C. $50\%$ daughters will be green and $50\%$ sons will be pink.
• D. All the daughters will be green and all the sons will be pink.

Answer 1

Answer: (D)

Grasshoppers show $XX-XO$ type of inheritance. Female grasshoppers have two $X$ chromosomes and male grasshoppers have one X chromosome. Let the chromosome with the recessive mutation producing pink body colour is X^p. Female grasshoppers with pink body colour will have X^pX^p. Male grass hopper will have one $X$ . In the cross between X^pX^p and XO, only two phenotypes will be produced: XX^p carrier females who will be green and X^pO pink body males.