Developmental stability in yellow dung flies (Scathophaga stercoraria): fluctuating asymmetry, heterozygosity and environmental stress

Abstract

The genetic basis for developmental stability, the ability of an organism to withstand genetic and environmental disturbance of development, is poorly understood. Fluctuating asymmetry (FA: small random deviations from symmetry in paired, bilateral traits) is the most widely used measure of developmental stability, and evidence suggests FA is weakly and negatively associated with genome‐wide heterozygosity. We investigated the genetic basis of developmental stability in the yellow dung fly. Fly lines were inbred for 16 generations at which time they were homozygous at the phosphoglucomutase (PGM) loci and PGM appears to influence FA in at least one other taxon. After 16 generations of inbreeding, lines homozygous for different PGM alleles were crossed and levels of FA for four metric traits were compared in the inbred and crossed flies. We also compared FA levels in these flies with previously gathered data on wild‐type (second generation outcrossed) flies, and additionally looked at the effects of two environmental stresses (larval food limitation and increased temperature) on FA. There were no significant differences in any measure of FA, nor in mean FA, in any trait when inbred and crossed flies were compared. Comparison of FA in these and wild flies also revealed no significant differences. Food limitation had no influence on FA, whereas heat stress increased FA of naturally, but not sexually, selected traits. Our results do not show a negative relationship between heterozygosity and FA, but support the notion that FA levels are stress, trait and taxon specific.

Fluctuating Asymmetry of Human Populations: A Review

“…Inbreeding has been linked to developmental instability in a number of plant [184] and animal [3,109,[185][186][187][188][189] species, though contrary results are common [188,[190][191][192][193][194]. As with mice raised under controlled conditions, inbred bird populations have greater fluctuating asymmetry when there is the additional stress of forest fragmentation [195].…”

Fluctuating asymmetry and genetic variability in the roe deer (Capreolus capreolus): a test of the developmental stability hypothesis in mammals using neutral molecular markers

“…It is noteworthy that most of the studies yielding a negative correlation between developmental instability (as measured by FA) and genetic variability were carried out on poikilotherms using nonmetric traits (e.g., Vrijenhoek and Lerman, 1982;Leary et al, 1983b; but see, e.g., Hosken et al (2000) and Réale and Roff (2003) for no such correlation with metric traits), whereas for homeotherms (for which FA is mostly quantified by metric traits, see Discussion section) no such relationship was found in the majority of cases (e.g., Hartl et al, 1991;Sert et al, 2005; for a review see Novak et al, 1993). In line with this, a meta-analysis conducted by Vllestad et al (1999) yielded the tendency of a positive association between FA and heterozygosity in homeotherms and the tendency of a negative association for poikilotherms whereas altogether there was 'only a weak association between heterozygosity and FA' (Vllestad et al, 1999, page no.…”

Size polymorphism and fluctuating asymmetry of Artemia (Branchiopoda: Anostraca) populations from the Crimea

“…There is little evidence for specific genes that govern FA per se; numerous studies show that FA levels in various characters are influenced by dominance and especially epistatic interactions among genes (Leamy and Klingenberg, 2005). There are some evidences that there is a relation between heterozygosity of individuals and expression of FA; FA negatively associated with genome-wide heterozygosity (Leary et al, 1984;Mitton, 1993;Zakharov, 1987;Fava and Martini, 1988;Whitlock, 1996;Pustovoit, 2010), but such relation for some traits is absent (Hosken et al, 2000;Pustovoit, 2010). In nature in polyploid individuals, as compared to diploid ones, phenotype stabilization (decrease of FA) may actually take place (Mesaroš et al, 1995;Mezhzherin and Kokodii, 2009).…”