Endangered Animals and What Are We Doing to Save 'em? - Cryogenic Preservation
In order to understand this topic, let's first answer some questions critical to it's background...
1) What we mean by the term 'endangered species?
An endangered species is an animal or plant that's considered at risk of extinction.
2)Why do we need to conserve the species becoming extinct?
Image credits: Roni Bintang
Extinction is supposed to be a natural phenomena. However, the current mass extinction of animal species at an unprecedented rate is largely caused by anthropogenic actions.The rate of species extinction is estimated at 100 to 1000 times higher than natural background rates. Progressive habitat fragmentation and destruction is resulting in accelerated decline of biodiversity on a global scale.
The Rivet Popper Hypothesis, proposed by Paul Ehrlich explains the importance of species richness in the maintenance of the ecosystem. Ecological interactions are extremely complex and intertwined and sometimes, the loss of a single species may have much larger implications than we can foresee (known as the vortex-effect).
What can we do to save the endangered species?
Over decades, captive breeding programs of non-domestic species were characterized by efforts to optimize species-specific husbandry, to increase studbook-based animal exchange, and to improve enclosure designs.
Several countries have imposed laws and action plans for the protection of these animals by ex-situ and in-situ means.
But even so, the extinction of several critically endangered species is sometimes irreversible.
And that's why the role of Assisted reproduction technology (ART) in wildlife species conservation is so crucial. In-depth-knowledge of reproductive anatomy and physiology are an important prerequisite and currently, this technology is available for approximately 250 species, mainly mammals and birds. Taxonomically closely related domestic or less endangered model species may serve as a blue-print for developing suitable protocols for endangered wildlife species. The first species ever to make use of ART is the California condor(Gymnogyps californianus). This species of gymnosperm had gone extinct in the wild way back in the year 1987 due to lead poisoning. Fortunately, artificial incubation, foster parenting, or hand-rearing, a ban of lead ammunition and most importantly, the ART have restored a largely independent wild population.
Some examples of ART include: i)Artificial insemination (AI)
ii) Ovum pick up (OPU)
iii)In vitro fertilization (IVF) and embryo transfer (ET)
iv) Intracytoplasmatic sperm injection (ICSI)
v) Somatic cell nuclear transfer (SCNT)
vi) Inner cell mass (ICM) and
vii) Stem cell-associated techniques (SCAT).
But all these major techniques more or less require intact preservation of the genetic material, which is conferred by 'Cryopreservation'.
Image source: METHODS article
Front. Microbiol., 28 January 2021
Sec. Aquatic Microbiology
https://doi.org/10.3389/fmicb.2020.597653
Blood, tissue samples, seminal fluids, eggs or cell cultures can be extracted with high-end biotechnological tools and preserved. The hence cultured cell lines can be frozen, protected with glycerol or DMSO, and stored in liquid nitrogen containers for many years. Such cryopreserved tissues and cell lines provide a viable and expandable source of genetic material and living cells that offer manifold possibilities for molecular and basic research.
References
https://www.sciencedirect.com/science/article/pii/S0093691X21001321
Reproductive sciences in animal conservation: progress and prospects
W.V. Holt, J.L. Brown, P. Comizzoli (Eds.), Advances in experimental medicine and biology, vol. 753, Springer (2014)
M.E. Hunter, S.M. Hoban, M.W. Bruford, G. Segelbacher, L. Bernatchez
Next-generation conservation genetics and biodiversity monitoring
Evol. Appl., 11 (7) (2018), pp. 1029-1034, 10.1111/eva.12661
