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Using the Koala (Phascolarctos cinereus) as a Case Study to Illustrate the Development of Artificial Breeding Technology in Marsupials: an Update

  • Stephen D. JohnstonEmail author
  • William V. Holt
Chapter
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 1200)

Abstract

The successful development and application of an assisted breeding program in any animal relies primarily on a thorough understanding of the fundamental reproductive biology (anatomy, physiology and behaviour) of the species in question. Surely, the ultimate goal and greatest hallmark of such a program is the efficacious establishment of a series of reliable techniques that facilitate the reproductive and genetic management of fragmented populations, both in captivity and in the wild. Such an achievement is all that more challenging when knowledge of the reproductive biology of that species is essentially rudimentary and without adequate models to compare to. Using the koala (Phascolarctos cinereus) as a case study, this chapter provides insights into the development of a concept that began as small undergraduate student project but that subsequently evolved into the first-ever successful artificial insemination of a marsupial. Apart from this historical perspective, we shall also provide a brief review of the current reproductive biology of the koala, discuss technical elements of current assisted breeding technology of this species, its application to the closely related wombat, and the potential role it might play in helping to conserve wild koala populations in the form of a live koala genome bank. There is little doubt that the unique reproductive biology and tractability of the koala has been a benefit rather than a hindrance to the success of artificial breeding in this species.

Keywords

Koala Phascolarctos cinereus Assisted breeding technology Reproductive biology Semen collection Semen cryopreservation Oestrous detection Induction of ovulation Artificial insemination 

Notes

Acknowledgements

The success of the koala ART program has largely been achieved through the dedication and support of a wide range of scientific collaborators, post-graduate students and zoological institutions. In alphabetic order, we are extremely grateful for the contribution and support of Dr Camryn Allen, Dr Katie Ballantyne, Ms Michele Barnes, Prof Ken Beagley, Ms Michelle Burridge, Mr Kevin Bradley, Prof Randal Cameron, Prof Frank Carrick, Dr Ron Cox, Dr Jon Curlewis, Mr Robert Douglas, Dr Bill Ellis, Prof Jaime Gosalvez, Ms Lyndal Hulse, Dr Carmen Lopez-Fernandez, Mr Alan Lisle, Dr Tamara Keeley, Prof Michael McGowan, Dr Allan McKinnon, Mr Al Mucci, Mr Paul O’Callaghan, Dr Vere Nicolson, Ms K Nilsson, Dr Nancy Phillips, Dr Michael Pyne, Prof Jennifer Seddon, Mr Peter Theilman and Dr Yeng Peng Zee.

References

  1. Adam-Hosking C. Current status of the koala in Queensland and NSW. World Wildlife Fund-Australia; 2017. https://www.wwf.org.au/ArticleDocuments/353/pub-current-status-of-the-koala-in-queensland-and-new-south-wales-19may17.pdf.aspx. Accessed 25 Feb 2019.
  2. Adams-Hosking C, McBride MF, Baxter G, Burgman M, de Villiers D, Kavanagh R, et al. Use of expert knowledge to elicit population trends for the koala (Phascolarctos cinereus). Divers Distrib. 2016;22:249–62.CrossRefGoogle Scholar
  3. Allen CD, McKinnon AJ, Lisle AT, D’Occhio MJ, Johnston SD. Use of a GnRH agonist and hCG to obtain an index of testosterone secretory capacity in the koala (Phascolarctos cinereus). J Androl. 2006;27:720–4.PubMedCrossRefPubMedCentralGoogle Scholar
  4. Allen CD, Burridge M, Mulhall S, Chafer ML, Nicolson VN, Pyne M, et al. Successful artificial insemination in the koala (Phascolarctos cinereus) using extended and extended-chilled semen collected by electroejaculation. Biol Reprod. 2008a;78:661–6.PubMedCrossRefPubMedCentralGoogle Scholar
  5. Allen CD, Burridge M, Chafer ML, Nicolson VN, Jago SC, Booth RJ, et al. Control of the koala (Phascolarctos cinereus) anterior pituitary-gonadal axis with analogues of GnRH. Reprod Fertil Dev. 2008b;20:598–605.PubMedCrossRefPubMedCentralGoogle Scholar
  6. Allen CD, de Villiers DL, Manning BD, Dique DS, Burridge M, Chafer ML, et al. Seasonal reproduction in wild and captive male koala (Phascolarctos cinereus) populations in south-east Queensland. Reprod Fertil Dev. 2010;22:695–709.PubMedCrossRefPubMedCentralGoogle Scholar
  7. Ballantyne K, Anderson S, Pyne M, Nicolson V, Mucci A, Lisle A, et al. Use of the gonadotrophin-releasing hormone antagonist azaline B to control the oestrous cycle in the koala (Phascolarctos cinereus). Reprod Fertil Dev. 2016a;28:1686–94.CrossRefGoogle Scholar
  8. Ballantyne K, Anderson S, Pyne M, Nicolson V, Mucci A, Lisle A, et al. The use of a synthetic progesterone, levonorgestrel (LNG), to control the oestrous cycle in the koala. Reprod Fertil Dev. 2016b;28:1526–32.CrossRefGoogle Scholar
  9. Blanshard W, Bodley K. Koalas. In: Vogelnest L, Woods R, editors. In medicine of Australian mammals. Collingwood: CSIRO Publishing; 2008. p. 227–328.Google Scholar
  10. Bodetti T, Johnston SD, Pospischil A, Knox C, Timms P. PCR detection of Chlamydia in koala (Phascolarctos cinereus) semen. Vet Rec. 2002;151:147–9.PubMedCrossRefPubMedCentralGoogle Scholar
  11. Bodetti TJ, Hengstberger K, Johnston S, Timms P. Evaluation of tetracycline, erythromycin, penicillin and streptomycin for decontaminating koala semen contaminated in vitro with chlamydiae. Vet Rec. 2003;153:588–59.PubMedCrossRefPubMedCentralGoogle Scholar
  12. Busby E, Soeta S, Sherwood N, Johnston S. Molecular analysis of the koala reproductive hormones and their receptors: gonadotrophin-releasing hormone (GnRH), follicle-stimulating hormone β and luteinising hormone β with localisation of GnRH. J Neuroendocrinol. 2014;26:870–87.PubMedCrossRefPubMedCentralGoogle Scholar
  13. Chapman JA, Leigh CM, Breed WG. The zona pellucida of the koala (Phascolarctos cinereus): its morphogenesis and thickness. J Anat. 2006;209:393–400.PubMedPubMedCentralCrossRefGoogle Scholar
  14. Charlton BD, Frey R, McKinnon AJ, Fritsch G, Fitch WT, Reby D. Koalas use a novel vocal organ to produce unusually low-pitched mating calls. Curr Biol. 2013;23:R1035–6.PubMedCrossRefPubMedCentralGoogle Scholar
  15. Dief HHA. Chlamydial disease of the male koala (Phascolarctos cinereus) reproductive tract. Master of philosophy thesis. Gatton: University of Queensland; 2011.Google Scholar
  16. Ellis W, FitzGibbon S, Pye G, Whipple B, Barth B, Johnston S, et al. The role of bioacoustic signals in koala sexual selection: insights from seasonal patterns of associations revealed with GPS-proximity units. PLoS One. 2015;10:e0130657.PubMedPubMedCentralCrossRefGoogle Scholar
  17. Feige S, Nilsson K, Phillips CJC, Johnston SD. Heterosexual and homosexual behaviour and vocalisations in captive female koalas (Phascolarctos cinereus). Appl Anim Behav Sci. 2007;103:131–45.CrossRefGoogle Scholar
  18. Gallegos G, Ramos B, Santiso R, Goyanes V, Gosálvez J, Fernández JL. Sperm DNA fragmentation in infertile men with genitourinary infection by Chlamydia trachomatis and Mycoplasma. Fertil Steril. 2008;90:328–34.PubMedCrossRefPubMedCentralGoogle Scholar
  19. Gonzalez-Astudillo V, Allavena R, McKinnon A, Larkin R, Henning J. Decline causes of koalas in South East Queensland, Australia: a 17-year retrospective study of mortality and morbidity. Sci Rep. 2017;7:42587.  https://doi.org/10.1038/srep42587.CrossRefPubMedPubMedCentralGoogle Scholar
  20. Gosalvez J, Holt WV, Johnston SD. Sperm DNA fragmentation and its role in wildlife conservation. Adv Exp Med Biol. 2014;753:357–84.PubMedCrossRefPubMedCentralGoogle Scholar
  21. Handasyde KA, McDonald IR, Than KA, Michaelides J, Martin RW. Reproductive hormones in the koala. In: Lee AK, Handasyde KA, Sanson GD, editors. Biology of the koala. Chipping North: Surrey Beatty; 1990. p. 203–10.Google Scholar
  22. Harding H, Aplin K. Phylogenetic affinities of the koala (Phascolarctidae; Marsupialia): a reassessment of the spermatozoal evidence. In: Lee AK, Handasyde KA, Sanson GD, editors. Biology of the koala. Chipping North: Surrey Beatty; 1990. p. 1–31.Google Scholar
  23. Harding HR, Carrick FN, Shorey CD. Special features of sperm structure and function in marsupials. Baltimore and Munich: Spermatozoon, Urban & Schwarzenberg; 1979. p. 289–303.Google Scholar
  24. Harding H, Carrick F, Shorey C. Acrosome development during spermiogenesis and epididymal sperm maturation in Australian marsupials. In: The sperm cell. Dordrecht: Springer; 1983. p. 411–4.CrossRefGoogle Scholar
  25. Harding H, Carrick F, Shorey C. The affinities of the koala Phascolarctos cinereus (Marsupialia: Phascolarctidae) on the basis of sperm ultrastructure and development. In: Archer M, editor. Possums and opossums: studies in evolution. Sydney: Surrey Beatty and Royal Zoological Society of New South Wales; 1987. p. 353–64.Google Scholar
  26. Hogan LA, Janssen T, Johnston SD. Wombat reproduction (Marsupialia; Vombatidae): an update and future directions for the development of artificial breeding technology. Reproduction. 2013;145:R157–73.PubMedCrossRefPubMedCentralGoogle Scholar
  27. Holt WV. Cryobiology, wildlife conservation and reality. CryoLetters. 2008;29:43–52.PubMedPubMedCentralGoogle Scholar
  28. Holt WV, Bennett PM, Volobouev V, Watson PF. Genetic resource banks in wildlife conservation. J Zool. 1996;238:531–44.CrossRefGoogle Scholar
  29. Holt WV, Penfold LM, Johnston SD, Temple-Smith P, McCallum C, Shaw J, et al. Cryopreservation of macropodid spermatozoa: new insights from the cryomicroscope. Reprod Fertil Dev. 1999;11:345–53.PubMedCrossRefPubMedCentralGoogle Scholar
  30. Hughes R. Light and electron-microscope studies on spermatozoa of koala, Phascolarctos cinereus (Marsupialia). J Anat. 1977;124:513.Google Scholar
  31. Hulse LS, Hickey D, Mitchell JM, Beagley KW, Ellis W, Johnston SD. Development and application of two multiplex real-time PCR assays for detection and speciation of bacterial pathogens in the koala. J Vet Diagn Investig. 2018;30:523–9.CrossRefGoogle Scholar
  32. Johnson RN, O’Meally D, Chen Z, Etherington GJ, Ho SY, Nash WJ, et al. Adaptation and conservation insights from the koala genome. Nat Genet. 2018;50:1102–11.PubMedPubMedCentralCrossRefGoogle Scholar
  33. Johnston SD. Reproductive biology of the Queensland koala (Phascolarctos cinereus adustus: Goldfuss). Unpublished Honours thesis. Brisbane: University of Queensland; 1994.Google Scholar
  34. Johnston SD. Studies towards the development of an artificial insemination protocol in the koala. PhD thesis. Brisbane: University of Queensland; 1999.Google Scholar
  35. Johnston SD. Challenges associated with the development and transfer of assisted breeding technology in marsupials and monotremes: lessons from the koala, wombat and short-beaked echidna. Reprod Fertil Dev. 2019.  https://doi.org/10.1071/rd18113CrossRefGoogle Scholar
  36. Johnston SD, Holt WV. Germplasm conservation in marsupials. In: Watson PF, Holt WV, editors. Cryobanking the genetic resource wildlife conservation for the future? London: Taylor and Francis; 2001. p. 203–25.Google Scholar
  37. Johnston SD, McGowan MR, Carrick FN, Cameron RDA. Towards the development of an artificial insemination programme for koalas (Phascolarctos cinereus). Proc 12th Int Congr Anim Reprod. 1992;4:1954–7.Google Scholar
  38. Johnston SD, McGowan MR, Carrick FN, Tribe A. Preliminary investigations into the feasibility of freezing koala (Phascolarctos cinereus) semen. Aust Vet J. 1993;70:424–5.PubMedCrossRefPubMedCentralGoogle Scholar
  39. Johnston SD, McGowan MR, Carrick FN, Cameron RD, Tribe A. Seminal characteristics and spermatozoal morphology of captive Queensland koalas (Phascolarctos cinereus adustus). Theriogenology. 1994;42:501–11.PubMedCrossRefPubMedCentralGoogle Scholar
  40. Johnston SD, O’Callaghan P, McGowan MR, Phillips NJ. Characteristics of koala (Phascolarctos cinereus adustus) semen collected by artificial vagina. J Reprod Fertil. 1997;109:319–23.PubMedCrossRefPubMedCentralGoogle Scholar
  41. Johnston SD, McGowan MR, O’Callaghan P. Assisted breeding technology for the conservation and propagation of Phascolarctos cinereus or how to make a koala pouch young. In: Proceedings of the Postgraduate Committee in veterinary science 1999. Sydney: University of Sydney; 1999. p. 119–216.Google Scholar
  42. Johnston SD, McGowan MR, O’Callaghan P, Cox R, Nicolson V. Studies of the oestrous cycle, oestrus and pregnancy in the koala (Phascolarctos cinereus). J Reprod Fertil. 2000a;120:49–57.PubMedCrossRefPubMedCentralGoogle Scholar
  43. Johnston SD, McGowan MR, O’Callaghan P, Cox R, Nicolson V. Natural and artificial methods for inducing the luteal phase in the koala (Phascolarctos cinereus). J Reprod Fertil. 2000b;120:59–64.PubMedCrossRefPubMedCentralGoogle Scholar
  44. Johnston SD, McGowan MR, Phillips NJ, O’Callaghan P. Optimal physicochemical conditions for the manipulation and short-term preservation of koala (Phascolarctos cinereus) spermatozoa. J Reprod Fertil. 2000c;118:273–81.PubMedCrossRefPubMedCentralGoogle Scholar
  45. Johnston SD, McGowan MR, O’Callaghan P, Cox R, Houlden B, Haig S, et al. Birth of koalas (Phascolarctos cinereus) at Lone Pine Koala sanctuary following artificial insemination. Int Zoo Yearb. 2003;38:160–72.CrossRefGoogle Scholar
  46. Johnston SD, O’Callaghan P, Nilsson K, Tzipori G, Curlewis JD. Semen-induced luteal phase and identification of a LH surge in the koala (Phascolarctos cinereus). Reproduction. 2004;128:629–34.PubMedCrossRefPubMedCentralGoogle Scholar
  47. Johnston SD, MacCallum C, Blyde D, McClean R, Lisle A, Holt WV. An investigation into the similarities and differences governing the cryopreservation success of koala (Phascolarctos cinereus: Goldfuss) and common wombat (Vombatus ursinus: Shaw) spermatozoa. Cryobiology. 2006;53:218–28.PubMedCrossRefPubMedCentralGoogle Scholar
  48. Johnston SD, Lopez-Fernandez C, Gosalbez A, Zee Y, Holt WV, Allen C, et al. The relationship between sperm morphology and chromatin integrity in the koala (Phascolarctos cinereus) as assessed by the sperm chromatin dispersion test (SCDt). J Androl. 2007;28:891–9.PubMedCrossRefPubMedCentralGoogle Scholar
  49. Johnston SD, Zee YP, Lopez-Fernandez C, Gosalvez J. The effect of chilled storage and cryopreservation on the sperm DNA fragmentation dynamics of a captive population of koalas. J Androl. 2012a;33:1007–15.PubMedCrossRefPubMedCentralGoogle Scholar
  50. Johnston SD, Satake N, Zee Y, Lopez-Fernandez C, Holt WV, Gosalvez J. Osmotic stress and cryoinjury of koala sperm: an integrative study of the plasma membrane, chromatin stability and mitochondrial function. Reproduction. 2012b;143:787–97.CrossRefGoogle Scholar
  51. Johnston SD, Mucci A, Ellis W. The role of captive koalas in koala conservation. In: Flint N, Melzer A, editors. A conserving Central Queensland’s koalas. Rockhampton: Koala Research Centre of Central Queensland, Central Queensland University; 2013. p. 54–9.Google Scholar
  52. Johnston S, Beagley K, Seddon J, Schultz B, Keeley T, et al. A new paradigm for koala conservation in SE Queensland: establishment of a living koala genome bank. In: Proceedings of the Queensland Environmental Law Association 2018 conference, 23–25 May 2018; 2018. p. 9–17.Google Scholar
  53. Kusuda S, Araki S, Makino T, Doi O, Ito H, Hashikawa H, et al. Noninvasive monitoring of reproductive activity based on fecal progestagen profiles and sexual behavior in koalas, Phascolarctos cinereus. Biol Reprod. 2009;81:1033–40.PubMedCrossRefPubMedCentralGoogle Scholar
  54. Kusuda S, Hashikawa H, Takeda M, Ito H, Goto A, Oguchi J, et al. Season- and age-related reproductive changes based on fecal androgen concentrations in male koalas, Phascolarctos cinereus. J Reprod Dev. 2013;259:308–13.CrossRefGoogle Scholar
  55. Larkin R, Palmieri C, Oishi M, Hulse L, Johnston SD. Ultrasonographic assessment of the male koala (Phascolarctos cinereus) reproductive tract. Res Vet Sci. 2018;117:219–23.PubMedCrossRefPubMedCentralGoogle Scholar
  56. MacCallum C, Johnston SD. Studies on the cryopreservation of common wombat (Vombatus ursinus) spermatozoa. Reprod Fertil Dev. 2005;17:727–32.PubMedCrossRefPubMedCentralGoogle Scholar
  57. Martin R, Handasyde K. The koala: natural history, conservation, management. 2nd ed. Kensington: University of New South Wales Press; 1999.Google Scholar
  58. McAlpine CA, Melzer A, Lunney D, Foley WJ, Adams-Hosking C, Lawler IR, et al. Conserving koalas in the 21st century: synthesising the dynamics of Australia’s koala populations. 2012. http://www.uq.edu.au/krn/ACEAS_Workshops_final_report.pdf. Accessed 25 Feb 2019.
  59. McAlpine C, Lunney D, Melzer A, Menkhorst P, Phillips S, Phalen D, et al. Conserving koalas: a review of the contrasting regional trends, outlooks and policy challenges. Biol Conserv. 2015;192:226–36.CrossRefGoogle Scholar
  60. McFarlane JR. Endocrine factors influencing reproduction in male non-eutherian mammals. PhD thesis. Brisbane: University of Queensland; 1990.Google Scholar
  61. Miller RR Jr, Sheffer CJ, Cornett CL, McClean R, MacCallum C, Johnston SD. Sperm membrane fatty acid composition in the Eastern grey kangaroo (Macropus giganteus), koala (Phascolarctos cinereus), and common wombat (Vombatus ursinus) and its relationship to cold shock injury and cryopreservation success. Cryobiology. 2004;49:137–48.PubMedCrossRefPubMedCentralGoogle Scholar
  62. Mitchell P. Social behaviour and communication of koalas. In: Lee AK, Handasyde KA, Sanson GD, editors. Biology of the koala. Chipping North: Surrey Beatty; 1990. p. 151–70.Google Scholar
  63. Monfort SL. “Mayday Mayday Mayday”. The millennium ark is sinking! Adv Exp Med Biol. 2014;753:15–31.PubMedCrossRefPubMedCentralGoogle Scholar
  64. Natural Resource Management Ministerial Council. National koala conservation and management strategy 2009–2014. Canberra. 2009. https://www.environment.gov.au/system/files/resources/165139fc-3ab5-4c96-8b15-d11a1ad882ab/files/koala-strategy.pdf. Accessed 25 Feb 2019.
  65. NSW Chief Scientist and Engineer. Report of the independent review into the decline of koala populations in key areas of NSW. 2016. http://www.chiefscientist.nsw.gov.au/__data/assets/pdf_file/0010/94519/161202-NSWCSE-koala-report.pdf. Accessed 25 Feb 2019.
  66. Obendorf DL. The pathogensis of urogenital tract disease in the koala. In: Australian wildlife, proceedings number 104. Sydney: University of Sydney Post-Graduate Committee in Veterinary Science; 1988. p. 649–55.Google Scholar
  67. Oishi M, Takahashi M, Amasaki H, Janssen T, Johnston SD. The seminiferous epithelial cycle and microanatomy of the koala (Phascolarctos cinereus) and southern hairy-nosed wombat (Lasiorhinus latifrons) testis. J Anat. 2013;222:380–9.PubMedPubMedCentralCrossRefGoogle Scholar
  68. Palmieri C, Hulse L, Pagliarani S, Larkin R, Higgins DP, Beagley K, et al. Chlamydia pecorum infection in the male reproductive system of koalas (Phascolarctos cinereus). Vet Pathol. 2018;56:300–6.  https://doi.org/10.1177/0300985818806963.. [Epub ahead of print].CrossRefPubMedPubMedCentralGoogle Scholar
  69. Pukazhenthi B, Comizzoli P, Travis AJ, Wildt DE. Applications of emerging technologies to the study and conservation of threatened and endangered species. Reprod Fertil Dev. 2006;18:77–90.PubMedCrossRefPubMedCentralGoogle Scholar
  70. Queensland Department of Environment Heritage and Protection. Nature conservation (koala) conservation plan 2006 and management program 2006–2016. 2006. http://www.uq.edu.au/krn/QLD_KoalaConservationPlan.pdf. Accessed 25 Feb 2019.
  71. Rhodes JR, Beyer HL, Preece HJ, McAlpine CA. South East Queensland koala population modelling study. Brisbane: UniQuest; 2015. https://environment.des.qld.gov.au/wildlife/koalas/pdf/seq-koala-population-modelling-study.pdf. Accessed 25 Feb 2019.Google Scholar
  72. Rhodes JR, Hood A, Melzer A, Mucci A. Queensland Koala Expert Panel: a new direction for the conservation of koalas in Queensland. A report to the Minister for Environment and Heritage Protection. Brisbane: Queensland Government; 2017. https://environment.des.qld.gov.au/wildlife/koalas/pdf/qld-koala-expert-panel-report-2017.pdf. Accessed 25 Feb 2019.Google Scholar
  73. Rodger JC, Hughes R. Studies of the accessory glands of male marsupials. Aust J Zool. 1973;21:303–20.CrossRefGoogle Scholar
  74. Rodger JC, Mate KE. Marsupial gametes and fertilisation. Today’s Life Sci. 1993;5:28–33.Google Scholar
  75. Rodger JC, Cousins SJ, Mate KE. A simple glycerol-based freezing protocol for the semen of a marsupial Trichosurus vulpecula, the common brushtail possum. Reprod Fertil Dev. 1991;3:119–25.PubMedCrossRefPubMedCentralGoogle Scholar
  76. Rodger JC, Paris DB, Czarny NA, Harris MS, Molinia FC, Taggart DA, et al. Artificial insemination in marsupials. Theriogenology. 2009;71:176–89.PubMedCrossRefPubMedCentralGoogle Scholar
  77. Schultz B, Hulse L, Nicolson V, Larkin R, Bromfield E, Nixon B, et al. Prolonged chilled preservation and preliminary investigations of energy production of koala spermatozoa. In: 13th int symp spermatology, 11–14th May 2018, Stockholm; 2018.Google Scholar
  78. Shaw G. Reproduction. In: Armati PJ, Dickman CR, Hume ID, editors. Marsupials. Cambridge: Cambridge University Press; 2006.Google Scholar
  79. Silva M, Niño MA, Letelier C, Godoy RH, Adams GP, Ratto MH. Is ovulation-inducing factor (OIF) present in the seminal plasma of rabbits? In: Annual meeting of the Society for the Study of Reproduction, Milwaukee; 2010.Google Scholar
  80. Taggart DA, Steele VR, Schultz D, Dibben R, Dibben J, Temple-Smith PD. Semen collection and cryopreservation in the Southern Hairy-nosed Wombat Lasiorhinus latifrons: implications for conservation of the Northern Hairy-nosed Wombat Lasiorhinus krefftii. In: Wells RT, Pridmore PA, editors. Wombats. Chipping North: Surrey Beatty; 1998. p. 180–91.Google Scholar
  81. Temple-Smith P, Taggart D. On the male generative organs of the koala (Phascolarctos cinereus): an update. In: Lee AK, Handasyde KA, Sanson GD, editors. Biology of the koala. Chipping North: Surrey Beatty; 1990. p. 33–54.Google Scholar
  82. Threatened Species Scientific Committee. Listing advice for the koala. 2012. http://www.environment.gov.au/biodiversity/threatened/species/pubs/197-listing-advice.pdf. Accessed 25 Feb 2019.
  83. Tyndale-Biscoe CH. Life of marsupials. Collingwood: CSIRO Publishing; 2005.CrossRefGoogle Scholar
  84. Tyndale-Biscoe CH, Renfree M. Reproductive physiology of marsupials. Cambridge: Cambridge University Press; 1987.CrossRefGoogle Scholar
  85. Wildt DE, Bush M, O’Brien SJ, Murray ND, Taylor A, Graves JA. Semen characteristics in free-living koalas (Phascolarctos cinereus). J Reprod Fertil. 1991;92:99–107.PubMedCrossRefPubMedCentralGoogle Scholar
  86. Wildt DE, Ellis S, Janssen D, Buff J. Toward more effective reproductive science for conservation. In: Holt WV, Pickard AR, Rodger JC, Wildt DE, editors. Reproductive science and integrated conservation. Cambridge: Cambridge University Press; 2003. p. 1–20.Google Scholar
  87. Woinarski J, Burbidge AA. The IUCN Red List of Threatened Species 2016: e.T16892A21960344. 2016.  https://doi.org/10.2305/IUCN.UK.2016-1.RLTS.T16892A21960344.en. Accessed 25 Feb 2019.
  88. Zee YP, Holt WV, Allen CD, Nicolson V, Burridge M, Lisle A, et al. Effects of cryopreservation on mitochondrial function and heterogeneity, lipid raft stability and phosphatidylserine translocation in koala (Phascolarctos cinereus) spermatozoa. Reprod Fertil Dev. 2007;19:850–60.PubMedCrossRefPubMedCentralGoogle Scholar
  89. Zee YP, Holt WV, Gosalvez J, Allen CD, Nicolson V, Pyne M, et al. Dimethylacetamide can be used as an alternative to glycerol for the successful cryopreservation of koala (Phascolarctos cinereus) spermatozoa. Reprod Fertil Dev. 2008;20:724–33.PubMedCrossRefPubMedCentralGoogle Scholar
  90. Zee YP, Lopez-Fernandez C, Arroyo F, Johnston SD, Holt WV, Gosalvez J. Evidence that single-stranded DNA breaks are a normal feature of koala sperm chromatin, while double-stranded DNA breaks are indicative of DNA damage. Reproduction. 2009a;138:267–78.PubMedCrossRefPubMedCentralGoogle Scholar
  91. Zee YP, Holt WV, Nicolson V, Pyne M, Johnston SD. Individual variability in post-thaw sperm survival in a captive koala population. Cryobiology. 2009b;59:69–74.PubMedCrossRefPubMedCentralGoogle Scholar

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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Wildlife Biology UnitSchool of Agriculture and Food Sciences, The University of QueenslandGattonAustralia
  2. 2.Academic Unit of Reproductive and Developmental MedicineThe University of SheffieldSheffieldUK

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