Recovery of gene diversity using long-term cryopreserved spermatozoa and artificial insemination in the endangered black-footed ferret
Level 5 - mechanism / opinion, no new human data
Non-human animal research and assisted reproductive protocol (CEBM Level 5).
OpenAlex W1902346417 · doi:10.1111/acv.12229
What was done
Sperm collected from six of the final 18 surviving black-footed ferrets (*Mustela nigripes*) was cryopreserved in liquid nitrogen for up to 20 years. Thawed samples were transabdominally inseminated into the uterine horns of female conspecifics within a captive breeding program, using protocols adapted from domestic ferrets and Siberian polecats.
What was found
Artificial insemination using thawed sperm containing as few as 3.4 × 10^6 motile spermatozoa resulted in eight live offspring, including from samples frozen for two decades. Integrating these offspring and their descendants into the breeding population increased gene diversity by 0.2%, lowered inbreeding measures by 5.8%, and prevented heterozygosity loss.
Why it matters
This confirms that decades-old cryopreserved germplasm can be successfully used via artificial insemination to reintroduce ancestral alleles and reduce inbreeding in critically endangered wildlife populations.
Limits
The abstract does not state the total number of inseminations performed or overall conception success rates. The absolute increase in gene diversity was modest (0.2%), and physiological or ecological fitness outcomes beyond standard genetic diversity metrics were not reported.
Cited by
- partial A single male black-footed ferret helped save the species from extinction by repopulating a breeding colony.