A Chip off the Old Block: A Model for the Evolution of Genomic Imprinting via Selection for Parental Similarity

A consequence of genomic imprinting is that offspring are more similar to one parent than the other, depending on which parent's genes are inactivated in those offspring. We hypothesize that genomic imprinting may have evolved at some loci because of selection to be similar to the parent of one sex or the other. We construct and analyze an evolutionary-genetic model of a two-locus two-deme system, in which one locus codes for a character under local selection and the second locus is a potential cis-acting modifier-of-imprinting. A proportion of males only migrate between demes every generation, and pre-breeding males are less fit, on average, than females. We examine the conditions in which an imprinting modifier allele can invade a population fixed for a non-imprinting modifier allele and vice versa. We find that the conditions under which the imprinting modifier invades are biologically restrictive (high migration rates and high values of recombination between the two loci) and thus this hypothesis is unlikely to explain the evolution of imprinting. Our modelling also shows that, as with several other hypotheses, polymorphism of imprinting status may evolve under certain circumstances, a feature not predicted by verbal accounts.

Key Words: mathematical model, modifier locus, parental effect

This article has been cited by other articles:

				M. M. Patten and D. Haig Reciprocally Imprinted Genes and the Response to Selection on One Sex Genetics, July 1, 2008; 179(3): 1389 - 1394. [Abstract] [Full Text] [PDF]

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