Practicing Success

Target Exam

CUET

Subject

Biology

Chapter

Principles of Inheritance and Variation

Question:

Who was the scientist that first observed the X body during spermatogenesis in insects?

Options:

Morgan

Henking

Mendel

Watson

Correct Answer:

Henking

Explanation:

The correct answer is Option (2) –Henking

The initial clue about the genetic/chromosomal mechanism of sex determination can be traced back to some of the experiments carried out in insects. In fact, the cytological observations made in a number of insects led to the development of the concept of genetic/chromosomal basis of sex-determination. Henking (1891) could trace a specific nuclear structure all through spermatogenesis in a few insects, and it was also observed by him that 50 per cent of the sperm received this structure after spermatogenesis, whereas the other 50 percent sperm did not receive it. Henking gave a name to this structure as the X body but he could not explain its significance. Further investigations by other scientists led to the conclusion that the ‘X body’ of Henking was in fact a chromosome and that is why it was given the name X-chromosome.