A colleague has developed a sophisticated technique for developing fruit flies f

Question

A colleague has developed a sophisticated technique for developing fruit flies from the single diploid nucleus generated by the first meiotic division of the oocyte.   In other words, her method allows you to activate the oocyte (using a lethally irradiated sperm) and then suppress the second meiotic division so that a fly develops from one of the two nuclei produced by only the first meiotic division (the other, called a polar body, does not develop). If the mother is heterozygous for a recessive mutation that causes white eyes, do you expect to see white-eyed progeny? If so, what fraction of the progeny are likely to be white-eyed? You should assume no recombination

Explanation / Answer

The mother is heterozygous for a recessive mutation of white eye.

Let the mother's genotype be ‘Ww’. After Meiosis I, (if no recombination occurs), one cell will have 'ww' and the other will have ‘WW’. Both cells will be diploid. Now, if the cell having 'WW' is the polar body, then the cell having 'ww' genotype will develop into oocyte.

Now, if this oocyte having 'ww' genotype interacts with the lethally irradiated sperm, then there is a chance of having white-eyed progeny. And the fraction of progeny which will be white-eyed will be 100%.

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