Bachinskaya, A.A., 1914
Saccharomyces paradoxus is a wild yeast and the closest known species to the baker's yeast Saccharomyces cerevisiae. It is used in population genomics and phylogenetic studies to compare its wild characteristics to laboratory yeasts.
Saccharomyces paradoxus is mostly isolated from deciduous trees (oak, maple, birch), and in some rare occasions on insects and fruits. It is often found in sympatry with other Saccharomyces species. Like Saccharomyces cerevisiae, it has a worldwide distribution and it is mesophilic, which limits its natural distribution to low latitudes. However, Saccharomyces paradoxus typically grows at lower temperatures than Saccharomyces cerevisiae, resulting in a slight shift in its distribution toward cooler regions, like British islands and Eastern Canada.
Unlike most other Saccharomyces species, there is no evidence that Saccharomyces paradoxus has been domesticated by human. Accordingly, its biogeography is mostly marked by natural processes like limited migration, glacial refugia  and adaptation to climate. At least four genetically and phenotypically distinct populations of Saccharomyces paradoxus have been identified, corresponding to main geographical divisions: Europe (including West Siberia), Far East Asia (Japan, Eastern Siberia), North America (North American East and West coasts, Great Lakes region) and North-East America (Gaspé Peninsula, Saint Lawrence Valley and Appalaches), respectively. Representative strains of these populations exhibit partial post-zygotic isolation. A fifth population is represented by a singleton isolate from Hawaii. Some strains from the European population are found in North America and New Zealand and likely result from recent colonization events. Two isolates from South America, described as Saccharomyces cariocanus, are genetically indistinguishable but exhibit post-zygotic isolation when crossed to strains from the American population, due to chromosomal translocations.
Saccharomyces paradoxus is naturally homothallic, and is mostly found as diploid in the environment. Reproduction is mostly clonal and 99% of sexual reproduction occurs between spores from the same ascus. Like in other Saccharomyces species, heterothallism can be restored using standard genetic tools, to obtain stable haploid strains for experimental purposes. Post-zygotic isolation between strains of Saccharomyces paradoxus is commonly observed and could be either due to genetic divergence between populations or to chromosomal changes within populations.
- Dunham, MJ; Louis, ED (2011). "Yeast evolution and ecology meet genomics". Embo Reports 12: 8–10. doi:10.1038/embor.2010.204.
- Charron, G; Leducq, J-B; Bertin, C (2014). "Exploring the northern limit of the distribution of Saccharomyces cerevisiae and Saccharomyces paradoxus in North America". FEMS Yeast Research 14: 281–8. doi:10.1111/1567-1364.12100.
- Hyma, KE; Jay, JC (2013). "Mixing of vineyard and oak-tree ecotypes of Saccharomyces cerevisiae in North American vineyards". Molecular Ecology 22: 2917–30. doi:10.1111/mec.12155.
- Maganti, H; Bartfai, D; Xu, J (2012). "Ecological structuring of yeasts associated with trees around Hamilton, Ontario, Canada". FEMS Yeast Research 12: 9–19. doi:10.1111/j.1567-1364.2011.00756.x.
- Sniegowski, PD; Dombrowski, PG; Fingerman, E (2002). "Saccharomyces cerevisiae and Saccharomyces paradoxus coexist in a natural woodland site in North America and display different levels of reproductive isolation from European conspecifics". FEMS Yeast Research 1: 299–306. doi:10.1111/j.1567-1364.2002.tb00048.x.
- Naumov, GI; Naumova, ES; Sniegowski, PD (1998). "Saccharomyces paradoxus and Saccharomyces cerevisiae are associated with exudates of North American oaks". Canadian Journal of Microbiology 44: 1045–50. PMID 10029999.
- Sampaio, JP; Goncalves, P (2008). "Natural populations of Saccharomyces kudriavzevii in Portugal are associated with oak bark and are sympatric with S. cerevisiae and S. paradoxus". Applied and environmental microbiology 74: 2144–52. doi:10.1128/AEM.02396-07.
- Sweeney, JY; Kuehne, HA; Sniegowski, PD (2004). "Sympatric natural Saccharomyces cerevisiae and S. paradoxus populations have different thermal growth profiles". FEMS Yeast Research 4: 521–5. PMID 14734033.
- Johnson, LJ; Koufopanou, V; Goddard, MR (2004). "Population genetics of the wild yeast Saccharomyces paradoxus". Genetics 166: 43–52. PMID 15020405.
- Leducq, J-B; Charron, G; Samani, P (2014). "Local climatic adaptation in a widespread microorganism". Proceedings. Biological sciences / The Royal Society 281: 20132472. doi:10.1098/rspb.2013.2472.
- Liti, G; Carter, DM; Moses, AM (2009). "Population genomics of domestic and wild yeasts". Nature 458: 337–41. doi:10.1038/nature07743.
- Charron, G; Leducq, J-B; Landry, CR (2014). "Chromosomal variation segregates within incipient species and correlates with reproductive isolation". Molecular Ecology. doi:10.1111/mec.12864.
- Liti, G; Barton, DB; Louis, EJ (2006). "Sequence diversity, reproductive isolation and species concepts in Saccharomyces". Genetics 174: 839–850. PMID 16951060.
- Kuehne, HA; Murphy, HA; Francis, CA (2007). "Allopatric divergence, secondary contact, and genetic isolation in wild yeast populations". Current biology 17: 407–11. PMID 17306538.
- Zhang, HA; Skelton, A; Gardner, RC (2010). "Saccharomyces paradoxus and Saccharomyces cerevisiae reside on oak trees in New Zealand: evidence for migration from Europe and interspecies hybrids". FEMS Yeast Research 10: 941–7. doi:10.1111/j.1567-1364.2010.00681.x.
- Naumov, GI; James, SA; Naumova, ES (2000). "Three new species in the Saccharomyces sensu stricto complex: Saccharomyces cariocanus, Saccharomyces kudriavzevii and Saccharomyces mikatae". International Journal of Systematic and Evolutionary Microbiology 50: 1931–42. PMID 11034507.
- Tsai, IJ; Bensasson, D; Burt, A (2008). "Population genomics of the wild yeast Saccharomyces paradoxus: Quantifying the life cycle". Proceedings of the National Academy of Sciences of the United States of America 105: 4957–62. doi:10.1073/pnas.0707314105.