About $3\ \text{million}$ GM male mosquitoes were released in the Cayman Islands. Explain why releasing such large numbers of male mosquitoes did not immediately raise the risk of dengue fever transmission.
In Malaysia, GM male mosquitoes and non-GM male mosquitoes were both released to compare how far they dispersed and how long they survived in the wild. The GM mosquitoes were distinguishable because they also contained a gene for green fluorescent protein (GFP). Explain why fluorescent markers are used instead of antibiotic resistance genes in many examples of gene technology.
Suggest why this process is termed positive feedback.
Explain why, in gene technology, a promoter has to be transferred together with the desired gene.
Switching on the gene coding for tTA in mosquito larvae, instead of in the eggs, makes this method of controlling mosquito numbers more effective. Suggest why.
GM mosquitoes carrying the tTA gene can survive and reproduce normally when fed a diet containing the added chemical, $A$. With reference to Fig. 2.1, suggest how $A$ could stop the GM mosquitoes from dying.
Suggest how large numbers of adult GM male mosquitoes can be generated for release into the wild from an original stock of GM males.
Suggest why there is little risk that the gene carried by these GM mosquitoes will be passed to other organisms if GM mosquitoes escape or are released into the wild.