This study was undertaken by Wedekind Gutachten, Switzerland. Potentially synergistic genetic biocontrol technologies can be grouped into those that do not involve engineered DNA sequences and those that do. The former include the “sterile male” and the “Trojan Y chromosome” technologies. The latter include genetic constructs that lead males to produce only male fertile offspring while daughters are either sterile or non-viable (“daughterless carp”), or to various types of engineered gene-drive technologies that would be sexually propagated but could still reach 100% inheritance. The high inheritance would allow them to spread even if the introduced engineered DNA sequence reduced the fitness of the host, for example by killing female offspring or rendering them infertile. Some gene-drive technologies could therefore lead to the extinction of a problem population. However, unintended spread of the engineered drive sequence beyond the target population is possible. Worst-case scenarios of applying gene-drive technologies may therefore include the extinction of an entire species, and, if gene flow is possible as is the case in many cyprinid fishes, of related species. 

Considering the biological effectiveness, the relevant logistical factors of each techniques, the risks involved, and their likely public acceptability, the potentially most appropriate technique for deployment against carp in Australia is the Trojan Y chromosome technology, specifically the production and release of mirror-type sex-reversed YY individuals, combined with all measures that increase the survival and fecundity of these stocked animals.