Principles of Inheritance and Variation Test - 55

Sex determination was widely used previously for knowing the sex of the fetus. Some of the people who wanted an only male child as their offspring were misusing it for female foeticide. So, it was banned by the government of India.

So, the correct option is 'Female Foeticide'.

1) Spontaneous mutations are the mutations that occur naturally (may arise from error in DNA replication or Spontaneous Deamination of 5-Methyl-cytosine)

C. E. McClung began extensive research into the idea that the X element must have something to do with sex determination. First, McClung asserted that this strange chromosome be called the "accessory chromosome," because it appeared to have a separate purpose compared to the other chromosomes. Next, he decided to undertake a wide comparative study of spermatogenesis not just in insects but in many different organisms, including spiders and mice. While observing sperm generation in grasshoppers, McClung noted that the accessory chromosome did not behave as the other chromosomes did during the first meiotic division. Specifically, this "twelfth chromosome" was not distributed equally to the four sperm cells that arose from one grasshopper spermatogonium; instead, it was present in only half of them. This consistent pattern of segregation in the spermatogenesis of many different organisms caused McClung to speculate that there must be some fundamental reason for the generation of two types of sperm cells. McClung thought about the consequences of this 50/50 distribution of the accessory chromosome, and he pondered how this distribution probably resulted in two different kinds of zygotes. He also noted that there was really only one characteristic that varied among zygotes of many different species in 50/50 proportions, and that characteristic was sex. Thus, when he assembled all the evidence together, McClung came up with the proposal that the accessory chromosome must influence the determination of sex in a zygote.

So, the correct answer is 'Mc Clung'.

Gene's transcription and translation produces a protein which has a specific function to perform. Also, a protein is a chain of amino acids. These amino acids are coded by codons or base triplets. Each codon will code for a particular amino acid. Change in sequence of these base triplets/codons (due to mutation) will lead to code of different amino acid and ultimately it will lead to a different protein which may be functional or non-functional.

So, the correct answer is 'The change in nature and sequence of base triplets of DNA'.

Stevens was interested in the process of sex determination. While studying the mealworm, she found that the males made reproductive cells with both X and Y chromosomes whereas the females made only those with X. She concluded that sex is inherited as a chromosomal factor and that males determine the gender of the offspring. Not appreciated, yet. At the time, the chromosomal theory of inheritance was not yet accepted, and it was commonly believed that gender was determined by the mother and/or environmental factors. Most scientists did not embrace Stevens's theory immediately. Another researcher, Edmund Wilson, made a similar discovery at about the same time, but Stevens is generally considered to have made the larger theoretical leap (one which was ultimately proven correct).

So, the correct answer is 'Wilson and Stevens'.

So, the correct answer is option C.

So, the correct answer is 'Correns'.

So, the correct answer is 'AA,AA,BB'.

So, the correct answer is 'Formation of two types of gametes by one sex and one type by other sex'.