Oral Presentation ESA-SRB-APEG-NZSE 2022

The hope, reality and challenges of conserving amphibians and reptiles through genome storage and assisted reproduction (#153)

Simon Clulow 1
  1. Centre for Conservation Ecology and Genomics, University of Canberra, Canberra, ACT, Australia

Amphibians and reptiles are among the most threatened vertebrate taxa globally. Storing gametes and other live cells in genome resource banks and using assisted reproductive technologies (ARTs) to retrieve live animals from the stored material are two powerful, complementary tools for arresting and reversing biodiversity decline. However, the degree of development of ARTs and cryopreservation technologies in amphibians and reptiles differ markedly. These differences are explained in part by different perceptions of the taxa, but also to the very different reproductive anatomy and biology associated with the evolutionary transition from the aquatic to the terrestrial environment, and external to internal fertilisation and development. Artificial fertilisation with cryopreserved sperm is becoming a more widely developed and utilised technology for amphibians: > 30 species have had live, motile cells recovered post-freeze/thaw and several have produced reproductively competent progeny following artificial fertilisation. However, in contrast, artificial insemination leading to production of live young has been reported in few reptiles, and while sperm have been successfully cryopreserved, the production of live offspring generated from cryopreserved sperm has not been reported. In both amphibians and reptiles, a focus on sperm cryopreservation and artificial fertilisation or artificial insemination has been at the expense of the more challenging development of cryopreserving oocytes and embryos, which has not been achieved for either taxon. However, encouraging break throughs in fish oocytes and whole embryos using vitrification and laser warming hold great promise for amphibians. Alternative technologies such as the use of sophisticated stem cell/primordial germ cell cryopreservation and transplantation approaches also hold promise for the recovery of diploid and female genomes in cases where oocytes/embryos cannot be cryopreserved. I will discuss our group’s work on the development of cryopreservation technologies and ARTs for the conservation of amphibians and reptiles with a focus on what we can achieve now, ongoing challenges and where we are heading next.