Recombinant DNA techniques allow certain genes to be directly transplanted from one organism into distantly related species, which has the effect of imbuing the recipient organism with a new trait such as resistance to cold weather or the ability to produce insulin, according to Rensselaer Polytechnic. Possible drawbacks include the unintended release of modified organisms and the sometimes unpredictable results of direct gene insertion.
Direct manipulation of organisms' genes has unlocked a new world of speed and efficiency in selective breeding. By cutting and swapping genetic sequences, scientists are able to skip the lengthy, very wasteful process of cross-breeding and selective culling of organisms. Often, a direct gene swap can introduce the desired trait within a single generation, according to IfGene. This has permitted the economical production of insulin by bacteria, the improvement in agricultural yields and the distribution of an effective hepatitis B vaccine.
IfGene also notes several serious drawbacks to unregulated genetic manipulation. As is often the case with new technologies, much remains to be discovered about how individual genes interact with the organism's genome. In some cases, planting a new gene into an embryo has totally unexpected results. The accidental release of altered plants or animals, or even the microbes used in the process, is also potentially dangerous.