Strong Heterogeneity in Advances in Cryopreservation Techniques in the Mammalian Orders

Abstract

Between 1970 and 2012, vertebrate abundance has declined by 58% with an average annual decline of 2%, calling for serious action to prevent a mass extinction and an irreversible loss of biodiversity. Cryobanks and cryopreservation have the potential to assist and improve ex situ and in situ conservation strategies by storing valuable genetic material. A great deal of studies concerning cryopreservation have been performed within the class Mammalia, although no systematic overview has previously been presented. The objective of this study is therefore to evaluate the status, pattern and future of cryopreservation within Mammalia. A strong disproportional distribution of studies in examined orders is displayed. For the majority of examined orders less than 10% of species has been examined. However, the cryopreservation of germplasm has in several cases been successful and resulted in successful applications of assisted reproductive techniques (ARTs). Various obstacles are associated with the development of cryopreservation protocols, and among them the most prominent is interspecific differences in cryotolerance. Extrapolation of protocols in closely related species is considered the most applicable procedure, and a future supplement to overcome this problem is the examination and comparison of cryobiological traits. Successful protocols have been developed for the vast majority of domesticated mammals, which gives incentive for the further extrapolation of protocols in threatened species.

Genomic analyses suggest adaptive differentiation of northern European native cattle breeds

“…A possibility emerging from our findings, consistent with recommendations from earlier studies (Charlton et al, ), is the potential to infuse variability into genetically depauperate lineages by means of original genetic diversity from older cryopreserved samples. These older semen samples could represent some of the existing variability prior to dramatic declines in census size and may be considered for inclusion in conservation breeding plans.…”

“…This strategy can be applied to native breeds of cattle and other species by cryopreservation of spermatozoa and oocytes in a gene bank (Curry, 2000;Su et al, 2012). An increasing number of species will, in the near future, be managed with the help of cryopreservation techniques (Charlton et al, 2018), including initiatives such as The Frozen Ark Project (https://www.frozenark.org/). In Denmark, cryopreservation is now used for native livestock breeds including the Jutland cattle, and these collections can provide genetic material for ongoing conservation efforts.…”

The Increasing Role of Short-Term Sperm Storage and Cryopreservation in Conserving Threatened Amphibian Species

“…The generation of offspring derived from AF using frozen–thawed sperm (referred to from hereon as ‘cryo-derived offspring’) has been reported in a range of non-amphibian vertebrate taxa, including mammals [ 193 ], birds [ 194 , 195 ], and fish [ 196 , 197 ]. Whilst offspring have been successfully generated using cryopreserved sperm in a range of species, including in livestock and humans, there are few examples where offspring performance has been monitored throughout development, or in subsequent generations.…”

Modeling genetic benefits and financial costs of integrating biobanking into the conservation breeding of managed marsupials

“…Biobanking and ARTs are routinely used in human medical treatments (e.g., cancer biobanks or frozen strains of biomedical mouse models [Charlton et al., 2018; Patil et al., 2018]) and extensively in cattle (Mapletoft & Hasler, 2005), sheep (Amiridis & Cseh, 2012), and poultry (Silversides et al., 2012). Wildlife practitioners have not been able to draw on comparable levels of research investment (in monetary terms and commitment of sector resources).…”