Developmental buffering: how many genes?

The question of how phenotypic variation is regulated hasattracted an increasing amount of attention in recent years(Debat and David 2001; Flatt 2005). In particular, the dis-covery of the intriguing eects of mutations of heat-shockprotein 90 (Hsp90) on phenotypic variability (Rutherford andLindquist 1998; Queitsch et al. 2002) sparked a great deal ofinterest in the question of whether there are specic genes withkey roles in the regulation of phenotypic variation and evolv-ability (e.g., Wagner et al. 1999).A number of studies have been published in the past sev-eral months that addressed a range of questions concerningthe buering role of Hsp90 in ies (Carey et al. 2006; Debatet al. 2006; Milton et al. 2006; Gibert et al. 2007), sh (Yeyatiet al. 2007) and plants (Sangster et al. 2007). Together withsome other recent studies, these articles oer some new per-spectives on the genetic basis of developmental buering.