Common goals, different stages: the state of the ARTs for reptile and amphibian conservation (original) (raw)
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Amphibians and reptiles are experiencing serious declines, with the number of threatened species and extinctions growing rapidly as the modern biodiversity crisis unfolds. For amphibians, the panzootic of chytridiomycosis is a major driver. For reptiles, habitat loss and harvesting from the wild are key threats. Cryopreservation and other assisted reproductive technologies (ARTs) could play a role in slowing the loss of amphibian and reptile biodiversity and managing threatened populations through genome storage and the production of live animals from stored material. These vertebrate classes are at different stages of development in cryopreservation and other ARTs, and each class faces different technical challenges arising from the separate evolutionary end-points of their reproductive biology. For amphibians, the generation of live offspring from cryopreserved spermatozoa has been achieved, but the cryopreservation of oocytes and embryos remains elusive. With reptiles, spermatozoa have been cryopreserved in a few species, but no offspring from cryopreserved spermatozoa have been reported, and the generation of live young from AI has only occurred in a small number of species. Cryopreservation and ARTs are more developed and advanced for amphibians than reptiles. Future work on both groups needs to concentrate on achieving proof of concept examples that demonstrate the use of genome storage and ARTs in successfully recovering threatened species to increase awareness and support for this approach to conservation.
Reptile and amphibian conservation through gene banking and other reproduction technologies
Russian Journal of …, 2011
More than 300 of the~6180 known reptile species are critically endangered or endangered, with more than 200 known amphibian species extinct, and~1230 of the~6800 known amphibian species are critically endangered or endangered. To assure the survival of these species conservation breeding programs (CBPs) are being established. The perpetuation of genetic variation is required in both CBPs and in natural populations, to maintain health and reproduction, and to enable adaptation to environmental change. However, over time genetic variation is often lost in CBPs and in small or fragmented natural populations. Reproduction technologies including gene banking through the use of sperm cryopreservation can perpetuate genetic variation. These technologies are being applied to amphibian conservation, however, their development and use for reptiles has received only sporadic attention. We review the use of reproduction technologies for the conservation of amphibians and reptiles including the hormonal induction of sperm and oocytes, their use in artificial fertilization, and the potentials of sperm cryopreservation for gene banking. Support for the use of reproduction technologies, and the perpetuation of genetic variation of threatened amphibians and reptiles, will benefit from practical examples of the recovery of genetic variation from stored sperm, and its use to provide competent individuals for rehabitation programs and to supplement populations.
Animals
Multidisciplinary approaches to conserve threatened species are required to curb biodiversity loss. Globally, amphibians are facing the most severe declines of any vertebrate class. In response, conservation breeding programs have been established in a growing number of amphibian species as a safeguard against further extinction. One of the main challenges to the long-term success of conservation breeding programs is the maintenance of genetic diversity, which, if lost, poses threats to the viability and adaptive potential of at-risk populations. Integrating reproductive technologies into conservation breeding programs can greatly assist genetic management and facilitate genetic exchange between captive and wild populations, as well as reinvigorate genetic diversity from expired genotypes. The generation of offspring produced via assisted fertilisation using frozen–thawed sperm has been achieved in a small but growing number of amphibian species and is poised to be a valuable tool f...
Amphibian & Reptile Conservation, 2018
Global amphibian declines associated with anthropogenic causes, climate change, and amphibianspecific infectious diseases (e.g., chytridiomycosis) have highlighted the importance of biobanking amphibian genetic material. Genetic resource collections were the first to centralize the long-term storage of samples for use in basic science, including disciplines such as molecular evolution, molecular genetics, phylogenetics, and systematics. Biobanks associated with conservation breeding programs put a special emphasis on the cryopreservation of viable cells. These cell lines have a broader application, including the potential for genetic rescue and use in species propagation for population enhancement, such as captive breeding and reintroduction programs. We provide an overview of the most commonly used methods for the preservation of genetic resources, identify ways to standardize collection processes across biobanks, and provide decision trees to assist researchers in maximizing the potential use of their samples for both scientific research and the practice of species conservation. We hope that the collection and deposition of tissues preserved using methods that enable eventual cell line establishment will become routine practice among researchers, particularly herpetologists working in the field. While many major museums do not yet cryopreserve reproductive cells or cell lines, they contain the infrastructure and staff to maintain these collections if protocols and procedures are adapted. Collaboration between organizations can play an important future role in the conservation of amphibians, especially biobanks associated with research institutions and those pioneering techniques used in breeding programs.
Sperm collection and storage for the sustainable management of amphibian biodiversity
2019
Current rates of biodiversity loss pose an unprecedented challenge to the conservation community, particularly with amphibians and freshwater fish as the most threatened vertebrates. An increasing number of environmental challenges, including habitat loss, pathogens, and global warming, demand a global response toward the sustainable management of ecosystems and their biodiversity. Conservation Breeding Programs (CBPs) are needed for the sustainable management of amphibian species threatened with extinction. CBPs support species survival while increasing public awareness and political influence. Current CBPs only cater for 10% of the almost 500 amphibian species in need. However, the use of sperm storage to increase efficiency and reliability, along with an increased number of CBPs, offer the potential to significantly reduce species loss. The establishment and refinement of techniques over the last two decades, for the collection and storage of amphibian spermatozoa, gives confiden...
Resurrecting biodiversity: advanced assisted reproductive technologies and biobanking
Reproduction and Fertility
Biodiversity is defined as the presence of a variety of living organisms on the Earth that is essential for human survival. However, anthropogenic activities are causing the sixth mass extinction, threatening even our own species. For many animals, dwindling numbers are becoming fragmented populations with low genetic diversity, threatening long-term species viability. With extinction rates 1000–10,000 times greater than natural, ex situ and in situ conservation programmes need additional support to save species. The indefinite storage of cryopreserved (−196°C) viable cells and tissues (cryobanking), followed by assisted or advanced assisted reproductive technology (ART: utilisation of oocytes and spermatozoa to generate offspring; aART: utilisation of somatic cell genetic material to generate offspring), may be the only hope for species’ long-term survival. As such, cryobanking should be considered a necessity for all future conservation strategies. Following cryopreservation, ART/...
How to conserve our planet's rapidly disappearing biodiversity is one of the greatest challenges of our generation. Among terrestrial vertebrate taxa, amphibians are most at risk with 41% of all known species experiencing population declines and one-third threatened with extinction. Although many institutions have responded by establishing captive assurance colonies for several critically endangered amphibians, the resources provided by these conservation organizations will not be enough to save all species 'at risk' without a multi-pronged approach. Around the world, zoos, aquariums, governments, and conservation NGOs are beginning to establish amphibian gene banks to conserve, in perpetuity, the remaining extant genetic diversity for many of these critically endangered species. A suite of biomaterials has been targeted for cryoconservation including blood, cell cultures, tissues, spermatozoa, eggs, and embryos. Several international workshops on amphibian gene banking and assisted reproductive technologies have been held between 2010 and 2012, bringing together leading experts in the fields of amphibian ecology, physiology, and cryobiology to synthesize emerging trends for biobanking amphibian genetic resources, provide opportunities for collaboration, and discuss future research directions. The following review paper and summary will provide a synopsis of these international workshops, in particular the hopes, realities, and current challenges inherent to this applied research field.
The earth currently suffers from a bout of animal extinctions. The Frozen Ark Project is acting internationally in preserving the genetic resources of threatened wild species before they become extinct. Modern techniques make preservation of this material easier, and costs of sequencing genomes have declined drastically during the past 10 years. The project is vital because the extinction of a species results in the loss of not only the animal but also the genetic information accumulated over millions of years of evolution. It will give us the ability to invigorate conservation-breeding programmes and conserve material of practical value in the form of tissues, viable somatic cells, gametes, eggs and embryos. The Frozen Ark is not considered a substitute for saving the animals themselves but an essential ‘back-up’ to this activity. International collaboration between the world’s zoos, aquariums, museums and universities is developing to achieve this conservation effort of last resort. Zoos and aquariums are crucial to the project because they increasingly hold the last individuals of the most threatened species.
Reproduction, Fertility and Development, 2021
Amphibians are becoming increasingly reliant on captive breeding programs for continued survival. Assisted reproductive technologies including gamete cryopreservation and IVF can help reduce costs of breeding programs, provide insurance against extinction and assist genetic rescue in wild populations. However, the use of these technologies to produce reproductively mature offspring has only been demonstrated in a few non-model species. We aimed to optimise sperm cryopreservation in the threatened frog Litoria aurea and generate mature offspring from frozen–thawed spermatozoa by IVF. We tested three concentrations (1.4, 2.1 and 2.8M) of the cryoprotectants dimethylsulfoxide (DMSO) and glycerol with 0.3M sucrose. Using DMSO was more likely to result in recovery of sperm motility, vitality and acrosome integrity than glycerol, regardless of concentration, with forward progressive motility being most sensitive to damage. The lowest concentrations of 1.4 and 2.1M provided the best protec...