A new paper, A Maternal-Offspring Coadaptation Theory for the Evolution of Genomic Imprinting (open access), presents a theory of genomic imprinting which purports to explain some facets of the phenomenon via maternal-child interaction:
Imprinted genes are expressed either from the maternally or paternally inherited copy only, and they play a key role in regulating complex biological processes, including offspring development and mother-offspring interactions. There are several competing theories attempting to explain the evolutionary origin of this monoallelic pattern of gene expression, but a prevailing view has emerged that holds that genomic imprinting is a consequence of conflict between maternal and paternal gene copies over maternal investment. However, many imprinting patterns and the apparent overabundance of maternally expressed genes remain unexplained and may be incompatible with current theory....
This model is complementary to paradigm that David Haig has been promoting. If you read Haig's work you note that he does acknowledge that his theory predicts only a subset of the featuers of genomic imprinting, his major point is that the aspects not explained by the 'genetic conflict' model do not contradict hypothesis, they are simply unexplained. Haig offered perhaps that other forces, perhaps even random walk stochastic ones, play a role in fleshing out the details of how imprinting manifests. The above model is I think a good complement as it directly addresses a blind spot in Haig's theory.
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