But there aren't just negative impacts, there are also positive impacts.
Exchanging seeds with other areas and cross-pollinating them increases genetic diversity. Same as with putting sperm in liquid nitrogen and transporting it long distances, but if this is used to fertilise many females it can limit the diversity.
Seed banks are preserving genetic diversity.
Humans' immediate survival depends on a few species of grass (wheat) and tubers (potatoes). Many large companies like Monsanto (which is terrible) produce GE plants and then give them to farmers to plant. These plants usually can't produce another crop (or if they do, unfavourable characteristics come through as they might sell you heterozygous and not homozygous plants for favourable characteristics) or they can spread their pollen long distances infecting the gene pool with foreign DNA. They also make you pay for the seeds and they have copyrights over them - a farmer on near by land to another farmer growing a crop had a few stalks of corn from the other farmer and there was some kind of legal action taken by Monsanto.
Other examples include the CSIRO selectively breeding wheat to eliminate wheat rust and all of the effort put into rice to make it produce more rice more often, suitable to different locations and chemicals used. However, if this was a trait found in only a few rice plants, then the genetic diversity could be limited as a result.
And some animal examples include trying to resurrect the Tasmanian Tiger and possibly preserving genetic material from species about to be extinct for a time when there are more advanced technologies available.
