To make the GM males, the researchers inserted the gene that codes for the restriction endonuclease I-PpoI. This restriction endonuclease was known to damage the X chromosome of A. gambiae. Explain the meaning of the term restriction endonuclease and suggest why I-PpoI damages the X chromosome, but not the Y chromosome.
The researchers put the gene for I-PpoI and also a gene for green fluorescent protein (GFP) into one of the autosomes (a chromosome other than X or Y) of male mosquitoes. Explain why the researchers introduced the gene for GFP, as well as the gene for I-PpoI.
The researchers discovered that I-PpoI destroyed the X chromosome during meiosis in the GM male mosquitoes. As a result, these males could not make sperm carrying an X chromosome. However, I-PpoI was still active in zygotes formed when female gametes fused with sperm carrying a Y chromosome. Explain why this meant that the GM males produced no offspring at all.
Describe and suggest explanations for the differences between the mean numbers of adult females in the two sets of cages during the experiment.
Suggest possible difficulties that could arise if the technique of releasing GM male mosquitoes with the modified I-PpoI gene were used to try to control populations of A. gambiae that occur naturally in the wild.
Suggest possible difficulties that could arise if the technique of releasing GM male mosquitoes with the modified I-PpoI gene were used to try to control populations of \emph{A. gambiae} that occur naturally in the wild.