By Allison Kubo Hutchison
|Elizabeth Ann, the first cloned black-footed ferret recorded on January 29, 2021. US fish and wildlife service through AP.|
Elizabeth Ann is the first endangered species native to the United States to be cloned. The black-footed ferret was considered completely extinct due to habitat loss until a small colony was discovered in 1981. Conservationists ran a captive breeding program to preserve the species, but only seven females were able to reproduce, meaning that 40 years later all about 1,000 of the remaining black-footed ferrets have a limited gene pool. The lack of genetic diversity makes the population vulnerable to disease. Elizabeth Ann is the first step in introducing a new line in the family tree. After her predecessor Willa died in 1988, her remains were frozen in the San Diego Zoo’s Frozen Zoo facility.
The embryo that split and multiplied to become Elizabeth Ann was created using a process called somatic nuclear transfer. First, an egg is removed from a female and the egg’s chromosomes are removed. This leaves an egg with its entire packaging empty, but the instructions are missing. A nucleus is then removed from the genetic donor’s non-reproductive cells, which could be ability cells or fat cells. Then the core of the animal you want to clone is inserted into the empty egg. Eventually the egg is stimulated to grow by a small shock and it begins to split and divide like a normal embryo and becomes involved in a surrogate mother for pregnancy. This method has limitations and has had limited success due to the high fetal and neonatal mortality rates. In addition, developmental disorders were observed in some of the cloned animals.
It is important to note that these animals are not true copies of the original. When an egg is used by another individual, the mitochondrial DNA is not the same, even if it is the nuclear DNA. This is because the mitochondria came from the original egg and will not be replaced. However, they are 100% the same if an egg from the cloned animal is used. The egg used for Elizabeth Ann was from a house ferret.
Elizabeth Ann supports efforts by the U.S. Fish and Wildlife Service Revive & Restore, ViaGen Pet & Equine, San Diego Zoo Global, and the Association of Zoos and Aquariums to restore black-footed ferret species.