Hybridization, sex-specific genomic architecture and local adaptation

While gene flow can reduce the potential for local adaptation, hybridization may conversely provide genetic variation that increases the potential for local adaptation. Hybridization may also affect adaptation through altering sexual dimorphism and sexual conflict, but this remains largely unstudied. Here, we discuss how hybridization may affect sexual dimorphism and conflict due to differential effects of hybridization on males and females, and then how this, in turn, may affect local adaptation. First, in species with heterochromatic sexes, the lower viability of the heterogametic sex in hybrids could shift the balance in sexual conflict. Second, sex-specific inheritance of the mitochondrial genome in hybrids may lead to cytonuclear mismatches, for example, in the form of ‘mother’s curse’, with potential consequences for sex ratio and sex-specific expression. Third, sex-biased introgression and recombination may lead to sex-specific consequences of hybridization. Fourth, transgressive segregation of sexually antagonistic alleles could increase sexual dimorphism in hybrid populations. Sexual dimorphism can reduce sexual conflict and enhance intersexual niche partitioning, increasing the fitness of hybrids. Adaptive introgression of alleles reducing sexual conflict or enhancing intersexual niche partitioning may facilitate local adaptation, and could favour the colonization of novel habitats. We review these consequences of hybridization on sex differences and local adaptation, and discuss how their prevalence and importance could be tested empirically. This article is part of the theme issue ‘Linking local adaptation with the evolution of sex differences’

The nature of Op Art: Bridget Riley and the art of nonrepresentation

The monochrome paintings of the British Op artist Bridget Riley produced between 1960 and 1965, in common with a number of experimental arts and media practices of the 1960s, were characterised by a drift away from traditional representational techniques towards what are now described as nonrepresentational practices. The dynamics of the Op Art aesthetic and the critical writings that surround it bear striking similarities to much recent work on nonrepresentational thought. Based upon an engagement with Riley s early work and specifically the perception and understanding of nature it engendered, an argument can be made that suggests that despite claims to the contrary, Riley was engaged in a form of representational practice that rendered a new and fashionable understanding of cosmic nature. The multi-dimensional nature evoked in her aesthetic was designed to be experienced by the viewer in a precognitive, embodied fashion. In this there are strong echoes with the call made by nonrepresentational theorists who operationalise the same kind of cosmology to develop an evocative, creative account of the world. Both Op Art and nonrepresentational thought seem to build upon a shift in the representational register that occurred during the immediate post-war period, one which prompted representational practices which attempted to subjectify rather than objectify, to evoke instability and multi-dimensionality, and to exercise not only visual, oral and cognitive ways of knowing, but also the precognitive and the haptic. The complex co-relations between representation and nonrepresentation are apparent here, suggesting that it is problematic to emphasise one side of the duality over the other