Yeast Biodiversity: How Many and How Much?

Biodiversity is now a common word. Harper and Hawksworth (1995) tabulated the frequency of use of the term in Biosis and reported its first occurrence in 1988 followed by an increase to approximately 900 by 1994. A similar search of the PubMed database yielded a cumulative total of 1,361 hits by the end of 2003. By comparison, the number of articles using the word “yeast” is approaching 100,000. If the present trend continues, by the year 2016 searches for either word will produce in excess of 36,000 hits for that year only. The task at hand is to make similar predictions about yeast biodiversity. Biodiversity means different things to different individuals. Gaston (1996) reviewed several definitions and concluded that the concept is an abstract expression of all aspects of the variety of life. Recent publications dealing with yeast diversity, had they appeared only 15 years earlier, might have used instead such terms as taxonomy, ecology, or survey (Nout et al. 1997; Buzzini and Martini 2000; Fell et al. 2000; Poliakova et al. 2001; Gadanho et al. 2003; Granchi et al. 2003; Lachance et al. 2003a; Ganga and Martinez 2004; Renker et al. 2004) or even enzymology (Lamb et al. 1999). The Convention on Biological Diversity (Anonymous 1992) defines biological diversity as “the variability among living organisms from all sources including, inter alia, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems.” As with most things in our society, biodiversity became a tangible reality when it could be assigned a significant economic value. And as with most things in science, the recognition of biodiversity as a worthy research topic is predicated on measurability and the generation of testable hypotheses. The current urgency of the scientific study of biodiversity stems from the realization that only a small fraction (approximately 8%) of the total diversity of life is known (Stork 1999) and that species extinction is occurring at a measurable and increasing rate (Purvis and Hector 2000). Chapter 1