Assisted gene flow using cryopreserved sperm in critically endangered coral

Authors: HAGEDORN, MARY - Smithsonian Institute; PAGE, C. - Hawaii Institute Of Marine Biology; O'NEIL, KERI - Florida Fish And Wildlife Conservation Commission; FLORES, DAISY - Florida Marine Research Institute; TICHY, LUCAS - Radboud University; CONN, TRINITY - Pennsylvania State University; CHAMBERLAND, VALERIE - University Of Amsterdam; LAGER, CLAIRE - Smithsonian Institute; ZUCHOWICZ, NIKOLAS - Smithsonian Institute; LOHR, KATHRYN - University Of Florida; Blackburn, Harvey; VARDI, TALI - National Oceanic & Atmospheric Administration (NOAA); MARAVER, KRISTEN - Scripps Institute

Submitted to: Proceedings of the National Academy of Sciences (PNAS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/6/2021
Publication Date: 9/7/2021
Citation: Hagedorn, M., Page, C.A., O'Neil, K., Flores, D.M., Tichy, L., Conn, T., Chamberland, V., Lager, C., Zuchowicz, N., Lohr, K., Blackburn, H.D., Vardi, T., Maraver, K. 2021. Assisted gene flow using cryopreserved sperm in critically endangered coral. Proceedings of the National Academy of Sciences (PNAS). 118(38). Article e2110559118. https://doi.org/10.1073/pnas.2110559118.
DOI: https://doi.org/10.1073/pnas.2110559118

Interpretive Summary: Coral reefs are key components in many marine aquaculture systems and under threat due to climate change. To conserve coral genetic resources semen from a Florida coral population was cryopreserved and then used to mate with coral eggs from the Western Caribbean. The resulting offspring were shown to be progeny of the two populations. This work demonstrated how cryopreserved semen could be used to assist the transference of genetic resources to a genetic and geographically different population. It underscores the important role gene banking plays in conserving genetic resources and facilitating the use of genetic variability.

Technical Abstract: Assisted gene flow (AGF) is a conservation intervention to accelerate plant and animal adaptation to climate change by importing genetic diversity into at-risk populations. Corals exemplify both the need for AGF and its technical challenges; corals have declined in abundance, suffered reproductive failures, and struggled to adapt to climate change, yet mature corals cannot be easily moved for breeding and gametes lose viability within hours. Here, we report the first successful demonstration of AGF in corals using cryopreserved sperm. We fertilized Acropora palmata eggs from the Western Caribbean (Curaçao) with cryopreserved 10 sperm from genetically distinct populations in the Eastern and Central Caribbean (Florida and Puerto Rico). We confirmed trans-regional parentage in the Curaçao-Florida offspring using 19,696 single nucleotide polymorphism markers. Thus, we provide the first evidence for reproductive compatibility of a Caribbean coral across a recognized barrier to gene flow. Six month survival of AGF offspring was 42%, the highest ever achieved in this species, yielding the largest wildlife population ever raised from cryopreserved material. By breeding a critically endangered coral across its range without moving adults, we show that AGF using cryopreservation is a viable conservation tool to increase genetic diversity and facilitate adaptation in threatened animal populations.