Editing Koala (section)

===Genetics and variations===
Three subspecies have been described: the Queensland koala (''Phascolarctos cinereus adustus'', [[Oldfield Thomas|Thomas]] 1923), the New South Wales koala (''Phascolarctos cinereus cinereus'', Goldfuss 1817), and the Victorian koala (''Phascolarctos cinereus victor'', [[Ellis Le Geyt Troughton|Troughton]] 1935). These forms are distinguished by [[pelage]] colour and thickness, body size, and skull shape. The Queensland koala is the smallest, with silver or grey short hairs and a shorter skull. The Victorian koala is the largest, with shaggier, brown fur and a wider skull.<ref name="Martin-Handasyde">{{cite book |author1=Martin, R. W. |author2=Handasyde, K. A. |year=1999 |title=The Koala: Natural History, Conservation and Management |publisher=New South Wales University Press |edition=2nd |isbn=978-1-57524-136-4 |url={{google books|plainurl=yes|id=RdWg_f5UI7cC}} |access-date=9 November 2015 |archive-date=6 April 2015 |archive-url=https://web.archive.org/web/20150406041539/http://books.google.com/books?id=RdWg_f5UI7cC |url-status=live }}</ref>{{rp|7}}<ref name="Houlden 1999">{{cite journal|author1=Houlden, B. A. |author2=Costello, B. H. |author3=Sharkey, D. |author4=Fowler, E. V. |author5=Melzer, A. |author6=Ellis, W. |author7=Carrick, F. |author8=Baverstock, P. R. |author9=Elphinstone, M. S. |year=1999|title=Phylogeographic differentiation in the mitochondrial control region in the koala, ''Phascolarctos cinereus'' (Goldfuss 1817)|journal=Molecular Ecology|volume=8|issue=6|pages=999–1011|doi=10.1046/j.1365-294x.1999.00656.x|pmid=10434420|bibcode=1999MolEc...8..999H |s2cid=36771770 }}</ref> The geographic limits of these variations are based on [[States and territories of Australia|state borders]], and their status as subspecies is disputed. A 1999 genetic study suggests koalas exist as a [[cline (biology)|cline]] within a single [[evolutionarily significant unit]] with limited [[gene flow]] between local populations.<ref name="Houlden 1999"/> In 2016, a comprehensive phylogenetic study did not support the recognition of any subspecies.<ref>{{Cite journal |last1=Neaves |first1=Linda E. |last2=Frankham |first2=Greta J. |last3=Dennison |first3=Siobhan |last4=FitzGibbon |first4=Sean |last5=Flannagan |first5=Cheyne |last6=Gillett |first6=Amber |last7=Hynes |first7=Emily |last8=Handasyde |first8=Kathrine |last9=Helgen |first9=Kristofer M. |last10=Tsangaras |first10=Kyriakos |last11=Greenwood |first11=Alex D. |last12=Eldridge |first12=Mark D. B. |last13=Johnson |first13=Rebecca N. |date=2 September 2016 |title=Phylogeography of the Koala, (Phascolarctos cinereus), and Harmonising Data to Inform Conservation |journal=PLOS ONE |language=en |volume=11 |issue=9 |pages=e0162207 |doi=10.1371/journal.pone.0162207 |issn=1932-6203 |pmc=5010259 |pmid=27588685 |doi-access=free|bibcode=2016PLoSO..1162207N }}</ref>

Other studies have found that koala populations are highly inbred with low [[genetic variation]].<ref>{{cite journal|author1=Houlden, B. A. |author2=England, P. R. |author3=Taylor A. C. |author4=Greville, W. D. |author5=Sherwin, W. B. |year=1996|title=Low genetic variability of the koala ''Phascolarctos cinereus'' in south-eastern Australia following a severe population bottleneck|journal=Molecular Ecology|volume=5|issue=2|pages=269–81|pmid=8673272|doi=10.1046/j.1365-294x.1996.00089.x |bibcode=1996MolEc...5..269H |s2cid=22441918 }}</ref><ref>{{cite journal|author1=Wilmer, J. M. W. |author2=Melzer, A. |author3=Carrick, F. |author4=Moritz, C. |year=1993|title=Low genetic diversity and inbreeding depression in Queensland Koalas|journal=Wildlife Research|volume=20|issue=2|pages=177–87|doi=10.1071/WR9930177}}</ref> Such low [[genetic diversity]] may have been caused by population declines during the late Pleistocene.<ref>{{cite journal|author1=Tsangaras, K. |author2=Ávila-Arcos, M. C. |author3=Ishida, Y. |author4=Helgen, K. M. |author5=Roca, A. L. |author6=Greenwood, A. D. |year=2012|title=Historically low mitochondrial DNA diversity in koalas (''Phascolarctos cinereus'')|journal=BMC Genetics|volume=13|pages=92|doi=10.1186/1471-2156-13-92|pmid=23095716|pmc=3518249|issue=1 |doi-access=free }}</ref> Rivers and roads limit gene flow and contribute to the isolation of southeast Queensland populations.<ref>{{cite journal |author1=Lee, K. E. |author2=Seddon, J. M. |author3=Corley, S. |author4=Williams, E. |author5=Johnston, S. |author6=Villers, D. |author7=Preece, H. |author8=Carrick, F. |year=2010 |title=Genetic variation and structuring in the threatened koala populations of Southeast Queensland |journal=Conservation Genetics |volume=11 |issue=6 |pages=2091–103 |doi=10.1007/s10592-009-9987-9|bibcode=2010ConG...11.2091L |s2cid=36855057 }}</ref> In April 2013, scientists from the [[Australian Museum]] and [[Queensland University of Technology]] announced they had [[Whole genome sequencing|fully sequenced]] the koala [[genome]].<ref name="Davey2013">{{cite news |title=Australians crack the code of koala's genetic blueprint |url=http://www.theage.com.au/national/australians-crack-the-code-of-koalas-genetic-blueprint-20130409-2hjfm.html |date=10 April 2013 |author=Davey, M. |newspaper=[[The Age]] |access-date=25 June 2013 |archive-url=https://web.archive.org/web/20130514133101/http://www.theage.com.au/national/australians-crack-the-code-of-koalas-genetic-blueprint-20130409-2hjfm.html |archive-date=14 May 2013 |url-status=live }}</ref>