Fifteen years ago a sheep called Dolly arrived into our world and caused a sensation. A living, breathing (and bleating) sheep created from an adult cell, Dolly was not the first animal to be cloned, but she became the most famous.
After Dolly’s birth, many scientists predicted flocks of all types of cloned species were now possible – as well as raising the controversial possibility that humans could be cloned one day.
BBC Future looks back at some of the landmark achievements and celebrated births over the decades. Everyone knows Dolly, but less known is that the first cloned animal success was a tadpole in the 1950s.
Bubbles around each animal correspond to the “buzz” that each cloning milestone has had on the field. To gauge the level of buzz, we turned to Google Scholar, which indexes the world's scientific literature across a whole range of disciplines. The data for each bubble came from tracking citations of different combinations of relevant terms (e.g. “cloning” and “human stem cells”).
Despite several successes, such as cows and mice, the timeline shows that he cloned zoo isn’t filled with as many species as perhaps scientists had hoped. Some successes were brief, with animals dying days after they were born. And some efforts that showed early promise in the lab have yet to result in a successful birth.
But cloning efforts have been boosted over the last 5-10 years thanks to huge improvements in tools and technologies. With these improvements, scientists still dream of a world where endangered animals can be saved from extinction, and where extinct animals can be miraculously brought back to life.
So, will we see mammoths roaming the planet again? Who knows.
And if you want to check out the data we used to create the graphic, you can find it here.