Transcript Slide 1
Genetic Engineering ANYTHING that humans do that changes the natural gene flow that would normally occur within a population. Natural Gene Flow • In nature, genes flow from one generation to the next in a natural order driven by selective pressures • The genes of animals that have a high fitness are passed on, and the ones that do not, go extinct • However, genetic engineering does not always select the characteristic with the highest fitness • Genetic engineering selects characteristics that are profitable or beneficial to humans Selective Breeding • Selective breeding is simply selecting a few individuals to serve as parents for your next generation. • This is not technically engineering new genes, but it does alter that natural gene flow • By selectively altering the gene flow, we can not only create favorable traits in organisms, but it also can alter how often the trait is observed. Inbreeding • Very often, inbreeding is the way selective breeding starts. • It is the easiest and fastest way to selectively increase the likelihood of a trait in offspring • Inbreeding is when you cross organisms with similar characteristics (often times the organisms are closely related) Inbreeding • Dogs, as well as a multitude of other organisms, are inbred to increase the likelihood of their enjoyable traits. • However, inbreeding has its risks. With an increased chance of gaining favorable recessive traits, you also increase your chance of non-favorable traits. • Remember, when a dominant and a recessive trait cross, you only see the dominant… But crossing the offspring of that organism, you have a 1 in 4 chance of seeing a pure bread recessive organism (which can be deadly) Hybridization • Hybridization is the crossing of NON-SIMILAR individuals (of different species) • This usual involves crossing members of different (but related) species • The hybrids often contain favorable traits from both parents and are hardier (this phenomena is known as hybrid vigor) • Most all commercial corn (as well as most crops) are hybrids. • Current corn crops make 10 times the corn!!! • Hybrids are nearly all sterile (the exception = Wholphin) and unable to create viable offspring Lion + Tiger = Liger Whale + Dolphin = Wholphin Making Ninja Turtles??? • We know that mutations are incredibly dangerous, and 9 times out of 10 result in death, so WHY is it that we spend millions of dollars trying to force mutations? • The problem with selective breeding is that it is ALWAYS confined to genes that are already found within a population • Mutations, dangerous as they may be, offer endless possibility Mutations • If a breeder wants to try and get a new trait into a population, but doesn’t want to wait for the tides of time and chance to give it, a mutation must be caused. • Mutations can be caused by agents or substances called mutagens. • Mutagens (such as radiation or chemicals) can occasionally cause favorable traits to enter a population • This has been extremely important in pharmaceutical drug creation