>> i don't think this will ever be possible, this is why people who are interested in deextinction ofmmoth for example, used genome editing techniques, to make specific changes in the genomes of an animal that is still alive to make it look more like the genome of the animal you want to try to deextinct. what you need is the places in the genome, the elephant genome, for instance that differed from the mammoth genome, and you would be able to have an elephant that has some of characteristics of a mammoth, for example, tolerance to cold or longer hair. >> tell me about that genome editing. is that possible? good that is possible today. and the technology to do multiple changes at once is being developed as we speak. there are some people in science that say if a species has gone extinct, there is a reason for it. let it be. how do you solve that problem? >> then and only then can we begin to think about what the other consequences of bringing that species back would be. >> the plight of the passenger pigeon is a popular topic for deextinction. in the 1700s their numbers were estimated