Testing theories for the evolution of genomic imprinting (Meeting)
Why are some genes imprinted, where the maternally or paternally inherited copies are preferentially expressed? Ever since the paradoxical pattern of imprinted gene expression was discovered evolutionary theories have strived to answer this question. Consequently, theories built on different fundamental assumptions have proliferated. Although these theories should make distinct and testable predictions, there have been few tests aimed at formally differentiating between these competing ideas. However, despite the general lack of such tests, the ‘kinship theory’, and especially its most prominent component, the ‘conflict hypothesis’, has emerged as the favored theory. This predominance is most notably reflected in the literature outside of evolutionary biology, where the conflict hypothesis is regularly used to interpret the functions and effects of imprinted genes. The conflict hypothesis rose to dominance because it appears to explain the effects of the first imprinted genes discovered. However, data from a broader array of genes in model species and emerging insights from non-model species appear to challenge whether one hypothesis adequately explains all occurrences of imprinting. We propose a working group composed of theoretical, computational and empirical biologists that will develop a set of formal predictions and devise tests to differentiate between competing models for the evolution of genomic imprinting. In doing so, we also expect to identify unexplored problems in evolutionary theory. Understanding why genes are imprinted also has important implications for evolutionary medicine since imprinted genes play a crucial role during pregnancy, in the manifestation of several behavioral disorders, and in some cancers.