Frozen zoo
A frozen zoo is a storage facility in which genetic materials taken from animals (e.g. DNA, sperm, eggs, embryos and live tissue) are stored at very low temperatures (−196 °C) in tanks of liquid nitrogen.
Several different species have been introduced to this technology, including the Pyrenean ibex, Black-footed ferret, and potentially the white rhinoceros.
The production of eggs, which in females is usually low, can be increased through hormone treatment to obtain 10–20 oocytes, dependent on the species.
[4] Several animals whose cells were preserved in frozen zoos have been cloned to increase the genetic diversity of endangered species, as of 2021[update].
[16][17] This organization operates as a charity with many different departments including the DNA laboratory, consortium, taxon expert groups, and the database.
[18] The hope for the future is for zoos and aquariums to be able to collect samples from their threatened and/or endangered species in house to help with conservation efforts.
RBC Director Steven Stice and animal and dairy science assistant professor Franklin West created the facility with the thought of saving endangered cat species.
Artificial insemination provides a remedy for animals who, due to anatomical or physiological reasons, are unable to reproduce in the natural way.
Oxidative stress is the most difficult to combat because of the highly reactive components of ROS, but some measures like adding certain proteins to limit freeze-thaw damage and increase the survival rate of the DNA.
Eight years later, DNA from these cells was inserted into a domestic-cow egg to create an embryo (trans-species cloning), which was then implanted in a domestic cow (Bos taurus).
[25][26] In 2020, the first cloned Przewalski's horse was born, the result of a collaboration between San Diego Zoo Global, ViaGen Equine and Revive & Restore.
[29] The somatic cell donor was a Przewalski's horse stallion named Kuporovic, born in the UK in 1975, and relocated three years later to the US, where he died in 1998.
[32] Once the foal matured, he was relocated to the breeding herd at the San Diego Zoo Safari Park,[32] so as to pass Kuporovic's genes into the larger captive Przewalski's horse population and increase the genetic variation of the species.
[27] To help mitigate inbreeding depression for two endangered species, the Black-footed ferret(Mustela nigripes), Revive & Restore facilitates on-going efforts to clone individuals from historic cell lines stored at the San Diego Zoo Wildlife Alliance Frozen Zoo.
[33][34] The cells of two 1980s wild-caught black-footed ferrets that never bred in captivity were preserved in the San Diego Wildlife Alliance Frozen Zoo.
In 2003 frozen cells from the last one (a female killed by a falling branch) were used to clone 208 embryos, of which 7 successfully implanted in goats, and one made it to term.
That one ibex died of respiratory failure just after birth; quite possibly as a result of the cloning process, its lungs had not developed properly.
[40] With the lack of natural mating occurring within the species due to the limited number of them, this sub-species provides researchers the opportunity for iPSC intervention.
