An example in a textbook and lecture discusses how the R allele for pesticide resistance arose in a northern population of Culex pipiens mosquitoes through mutation and became fixed in southern populations of the same species through natural selection and genetic drift acting on the allele.

1. An example in the textbook (and also in lecture) discusses the fixation of an allele for pesticide
resistance in two populations of Culex pipiens. In this example, the R allele for pesticide
resistance arose in the ancestral northern population by and it became fixed in the southern
populations as a result of mutation; natural selection natural selection; gene flow gene flow;
natural selection mutation; genetic drift