The Evolution of Genomic Imprinting

David Haig
The Botanical Museum; Harvard University

Genomic imprinting can be viewed as the modification of gene expression by past environments. That is, gene expression in the current generation is determined by whether a gene spent the previous generation in a male or female germline. My talk will consider circumstances in which natural selection would favor the 'adaptive' modification of behavior by past environments. In its simplest form, the genetic-conflict theory proposes that multiple paternity of a female's offspring favors differential expression of maternal and paternal alleles in offspring such that the expression of paternal alleles increases the cost of the offspring to its mother whereas the expression of maternal alleles reduces the cost to the mother. In its more general form, the theory applies to all interactions among relatives that have different maternal and paternal coefficients of relatedness (as may arise from differential dispersal of the sexes). The possibility that genomic imprinting could encode information about the mating patterns of particular males or about past levels of nutrition will also be discussed.