Experimental Studies of Group Selection: What Do They Tell US About Group Selection in Nature?

Abstract

The study of group selection has developed along two autonomous lines. One approach, which we refer to as the adaptationist school, seeks to understand the evolution of existing traits by examining plausible mechanisms for their evolution and persistence. The other approach, which we refer to as the genetic school, seeks to examine how currently acting artificial or natural selection changes traits within populations and focuses on current evolutionary change. The levels of selection debate lies mainly within the adaptationist school, whereas the experimental studies of group selection lie within the genetic school. Because of the very different traditions and goals of these two schools, the experimental studies of group selection have not had a major impact on the group selection debate. We review the experimental results of the genetic school in the context of the group selection controversy and address the following questions: Under what conditions is group selection effective? What is the genetic basis of a response to group selection? How common is group selection in nature?

The conversion of variance and the evolutionary potential of restricted recombination

“…Selection may then act on these additively acting alleles. Thus, the fixation or near fixation of epistatic partners associated with inbreeding, population bottlenecks, and population subdivision can expose alleles otherwise hidden from selection in large, panmictic populations (Wright, 1977;Wade et al, 1996;Goodnight and Stevens, 1997;Meffert, 2000;Wade, 2000;Barton and Turelli, 2004).…”

“…Recent QTL studies provide additional, more direct evidence that genes important to fitness do interact epistatically (Brockmann et al, 2000;Rü ppell et al, 2004;reviewed in Cheverud, 2000). Moreover, there is a growing body of evidence supporting the possibility that substantial epistatic variance can exist within and between natural populations and subpopulations (Hard et al, 1992;Goodnight and Stevens, 1997;Lair et al, 1997;Cheverud, 2000;Fenster and Galloway, 2000;Templeton, 2000;Bradshaw et al, 2005).…”

Conflicting levels of selection in the accumulation of mitochondrial defects in Saccharomyces cerevisiae

“…ref. 21), because antagonism among levels of selection can be explicitly demonstrated and experimentally manipulated, and because the conflict among levels of selection is relevant to medically important phenomena.…”

Future trends in Animal Breeding due to new genetic technologies

“…Although group selection has been tested in Tribolium (Wade, 1976 and1977;García and Toro, 1990;Goodnight and Stevens, 1997), there are few applications of group selection in domesticated species. In the classic experiment of Muir (1985 and1996), layers were housed in half-sib groups and selected as a group for either group livability or egg mass over 1 year of housing.…”