Assisted Reproductive Technologies for Wildlife Conservation

Assisted reproductive technologies (ARTs) have become indispensable tools for the preservation of genetic diversity and the reinforcement of fragile wild populations. These techniques encompass a suite of interventions, from gamete rescue and cryopreservation to in vitro fertilisation, embryo culture and transfer, as well as emerging approaches such as cloning and stem-cell–derived gametogenesis. By safeguarding germplasm through dedicated biobanks and enabling ex situ propagation, ARTs mitigate the demographic and genetic risks associated with small population sizes, habitat loss and poaching. Practical applications include post-mortem retrieval of sperm and oocytes, hormonal induction of ovulation in acyclic females, intracytoplasmic sperm injection to overcome gamete incompatibility and the establishment of embryonic stem cell lines for long-term genetic rescue. Collectively, these interventions support captive breeding, facilitate targeted gene flow between fragmented populations and offer a route to re-introduction or augmentation of critically endangered species. Ongoing research emphasises refinement of cryoprotectants, optimisation of culture media and ethical considerations for the application of advanced genomic methods in wildlife settings.

Research from Nature Portfolio

Comprehensive characterisation of post-mortem epididymal spermatozoa in a cornerstone bison species has provided detailed standards for morphology, motility and viability metrics, demonstrating that utilising a Tris-buffer extender with egg yolk preserves over half of motile cells after thawing. This work underpins the establishment of germplasm banks for species facing extreme genetic bottlenecks. In a seminal study on rhinoceros genetics, oocytes recovered from live Southern White Rhinoceros donors were matured in vitro and fertilised via intracytoplasmic sperm injection with Northern White Rhinoceros sperm, yielding blastocysts from which embryonic stem cell lines were derived. These embryos were cryopreserved for future transfer, exemplifying a roadmap for recovering alleles from functionally extinct lineages and enabling genetic continuance in other large mammals.

Assisted Reproductive Technologies for Wildlife Conservation publication trend

The graph below shows the total number of articles in assisted reproductive technologies for wildlife conservation across all publications each year (not limited to Nature Index journals).

Technical terms

Cryopreservation: The process of cooling and storing cells or tissues at sub-zero temperatures to maintain viability.

Epididymal spermatozoa: Sperm cells collected from the epididymis, often post mortem, as a source of genetic material.

Intracytoplasmic sperm injection (ICSI): A micromanipulation technique in which a single sperm cell is directly injected into an oocyte.

Germplasm bank: A repository for preserved genetic material, including sperm, oocytes, embryos and DNA samples.

Oviductal extracellular vesicles (oEVs): Membrane-bound particles secreted by the oviductal epithelium that carry proteins and RNAs to support gamete and embryo function.

References

1. Cloning for the Twenty-First Century and Its Place in Endangered Species Conservation. Annual Review of Animal Biosciences (2023).
2. The morphology, morphometry and functionality of fresh and cryopreserved wisent (Bison bonasus) epididymal spermatozoa. Scientific Reports (2023).
3. Embryos and embryonic stem cells from the white rhinoceros. Nature Communications (2018).
4. Oviductal Extracellular Vesicles Improve Post-Thaw Sperm Function in Red Wolves and Cheetahs. International Journal of Molecular Sciences (2020).