Varios

Hormones and Behavior 59 (2011) 369–374

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Hormones and Behavior
j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / y h b e h

Review

Genomic imprinting and mammalian reproduction
William T. Swaney ⁎
Behavioural Biology and Helmholtz Institute, Utrecht University, 3508 TB Utrecht, The Netherlands

a r t i c l e

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a b s t r a c t
Among animals, genomic imprinting is a uniquely mammalian phenomenon in which certain genes are monoallelically expressed according to their parent of origin. This silencing of certain alleles often involves differential methylation at regulatory regions associated with imprinted genes and must be recapitulated at every generation with the erasure and reapplication ofthese epigenetic marks in the germline. Imprinted genes encode regulatory proteins that play key roles in fetal growth and development, but they also exert wider effects on mammalian reproduction. Genetic knockout experiments have shown that certain paternally expressed imprinted genes regulate post-natal behavior in offspring as well as reproductive behaviors in males and females. These deficitsinvolve changes in hypothalamic function affecting multiple areas and different neurochemical pathways. Paternally expressed genes are highly expressed in the hypothalamus which regulates growth, metabolism and reproduction and so are well placed to influence all aspects of reproduction from adults to the resultant offspring. Coadaptation between offspring and mother appears to have played an importantrole in the evolution of some paternally expressed genes, but the influence of these genes on male reproductive behavior also suggests that they have evolved to regulate their own transmission to successive generations via the male germline. © 2010 Elsevier Inc. All rights reserved.

Article history: Received 1 April 2010 Revised 19 May 2010 Accepted 20 May 2010 Available online 26 May 2010Keywords: Genomic imprinting Imprinted genes Reproduction Sexual behavior Maternal behavior Hypothalamus Paternally expressed genes Coadaptation Conflict

Contents Introduction . . . . . . . . . . . . . . . . . . . . . Genomic imprinting mechanisms and reproduction . . Imprinting and reproduction in mammals . . . . . . . Imprinted gene effects in offspring. . . . . . . . . Imprinted gene effects infemales . . . . . . . . . Imprinted gene effects in males . . . . . . . . . . Reproduction and the evolution of genomic imprinting. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369 370 370 371 372 372 373 373

Introduction In the early 1980s, it became clear that the parental genomes in mammals were functionally non-equivalent (McGrath and Solter, 1984; Surani et al., 1984), a phenomenon termed ‘genomic imprinting’. A subset of autosomal genes is expressed not in accordance with classicalMendelian laws of inheritance, but according to the sex of the parent from which they are inherited. Imprinted genes are thus not expressed biallelically but in non-stochastic, monoallelic fashion from either the maternally donated allele or the paternally donated allele.

⁎ Fax: +31 30 2532837. E-mail address: w.t.swaney@uu.nl. 0018-506X/$ – see front matter © 2010 Elsevier Inc. All rights reserved....