Cloning is the process of making copies of a specific piece of DNA, usually a gene. When geneticists speak of cloning, they may not mean the process of making genetically identical copies of an entire organism, but of making a copy of a small piece of DNA. To date, the highest species to be cloned are non-human primates. There are currently strict NIH regulations against the cloning of humans; few groups support the cloning of entire humans, though the cloning of select organisms in host animals (e.g. growing replacement human hearts in pigs) is a long term goal of the scientific community. Recently, proof-of-concept experiments growing cloned rat organs in mice and via versa have demonstrated the feasibility of one day growing cloned human organs in host animals.
Cloning is used to replicate endangered species and avoid extinction. As announced in February 2021, cloning successfully created the first American endangered species: a black-footed ferret. It was duplicated from the genes of a black-footed ferret which died more than 30 years earlier, and born on December 10, 2020.