Genomic imprinting and the social brain

Abstract

Genomic imprinting refers to the parent-of-origin-specific epigenetic marking of a number of genes. This epigenetic mark leads to a bias in expression between maternally and paternally inherited imprinted genes, that in some cases results in monoallelic expression from one parental allele. Genomic imprinting is often thought to have evolved as a consequence of the intragenomic conflict between the parental alleles that occurs whenever there is an asymmetry of relatedness. The two main examples of asymmetry of relatedness are when there is partiality of parental investment in offspring (as is the case for placental mammals, where there is also the possibility of extended postnatal care by one parent), and in social groups where there is a sex-biased dispersal. From this evolutionary starting point, it is predicted that, at the behavioural level, imprinted genes will influence what can broadly be termed bonding and social behaviour. We examine the animal and human literature for examples of imprinted genes mediating these behaviours, and divide them into two general classes. Firstly, mother-offspring interactions (suckling, attachment and maternal behaviours) that are predicted to occur when partiality in parental investment in early postnatal offspring occurs; and secondly, adult social interactions, when there is an asymmetry of relatedness in social groups. Finally, we return to the evolutionary theory and examine whether there is a pattern of behavioural functions mediated by imprinted genes emerging from the limited data, and also whether any tangible predictions can be made with regards to the direction of action of genes of maternal or paternal origin.

Social Behavior and Autism Traits in a Sex Chromosomal Disorder: Klinefelter (47XXY) Syndrome

“…Isles et al (2006) have argued that parental origin of a gene impacts the development of social behavior. The differential expression of a gene depending on the parental origin of the gene is referred to as genomic imprinting.…”

Constraints and flexibility in mammalian social behaviour: introduction and synthesis

“…During foetal development, genomic imprinting, i.e. the fact that certain genes are expressed in a parent-of-origin-dependent manner [50], may have lasting effects on the development and later behaviour of siblings [51]. Other epigenetic processes that involve modification of DNA sequences that serve to modulate gene expression during pre-or post-natal development can also lead to predictable behavioural outcomes later in life [52].…”

Genomic imprinting and the evolutionary psychology of human kinship

“…Children with AS are proposed to express strongly behaviors that normally function to elicit maternal care, attention, and attachment (5,25). However, the overtly social personality of children with AS is combined with a profound deficit in communication (26).…”

“…Imprinted genes have been considered prime candidates for involvement in disorders of human social interaction, such as autism and schizophrenia, because of their predicted role in interactions among kin (4)(5)(6)(7)(8)(9). Not all social interactions promote imprinted gene expression, however.…”