This method requires a lot of time and effort because the construction of the virus is quite complicated. Another effect of infection is that information from viruses is not always incorporated into all cells in culture, making it necessary to breed selected organisms to isolate those with the desired gene (Macer). Pronuclear microinjection is another method of genetic manipulation. Linear fragments of DNA containing the desired gene are injected into the nucleus of a fertilized egg, where they will be embedded in random positions. The desired gene will eventually be expressed in a percentage of the resulting organisms. Although relatively simple, there is still control over the rate of expression of genes or the disruption of genes vital to the survival of organisms (Macer). Nuclear transfer is the most efficient method of genetic manipulation we have ever developed. Cultured cells are transfected with the desired genes; these cells can then be analyzed to determine whether DNA integration is successful. The selected cells are starved so that they do not divide, then the nucleus is inserted into the original egg. The transgenic animal is then born which, hopefully, expresses the desired gene (Macer). The greatest concern regarding genetic manipulation methods is the large number of failed animals, that is, animals that do not express the desired gene. What will be done with the failures? Should they be killed, and would this be merciful or cruel? Brin acknowledged human impatience, saying that for all their unusual and rapid successes in Elevation, terrestrial geneticists still had a long way to go with neo-dolphins and neo-chimpanzees; by galactic standards they had made great strides, but the Earthlings wanted even faster progress (Brin, 110). We should also try to fully evolve other species?