Is there a genomically imprinted social brain?

Abstract

Imprinted genes (IGs) are expressed or silenced according to their parent-of-origin. These genes are known to play a role in regulating offspring growth, development and infant behaviors such as suckling and ultrasonic calls. In adults, neurally expressed IGs coordinate several behaviors including maternal care, sex, feeding, emotionality, and cognition. However, despite evidence from human psychiatric disorders and evolutionary theory that maternally and paternally expressed genes should also regulate social behavior, little empirical data from mouse research exists. This paper discusses data from a recent study (Garfield et al., 2011) that the IG Grb10 governs unique aspects of mouse social behavior and interprets the relevance of these findings for the future of this field.

The evolution of genomic imprinting: theories, predictions and empirical tests

“…In contrast, the kinship theory is compatible with imprinted expression in adult tissues involved in social interactions (for example, brains and mammary glands; Brandvain et al , 2011). However, it should be noted that asymmetries of interests between matrigenes and patrigenes are dependent on several species-specific demographic factors, and that the regulation of social behaviors is complex, making clear-cut predictions on the direction of imprinting in adult brains especially challenging (Curley, 2011). Where a gene's expression cannot influence the fitness of kin, the kinship theory does not predict the evolution of imprinted expression.…”

Temporal dynamics of social hierarchy formation and maintenance in male mice

“…Although these tests reveal behaviour characteristics of individual mice and the relationship between two individuals at a given point in time, they do not provide information about how relationships develop over time or how relationships are adjusted within a large social network. Dominance in pairs of mice is usually assessed with dyadic tubetests (van den Berg, Lamballais, & Kushner, 2015;Curley, 2011;Wang et al, 2011), food, sex or other reward competition tests (Benner, Endo, Endo, Kakeyama, & Tohyama, 2014;Jupp et al, 2015;Nelson, Cunningham, Ruff, & Potts, 2015) and aggression tests (Branchi et al, 2013;Ginsburg & Allee, 1942). Problematically, results in these social contexts do not necessarily relate to overall social dominance within a larger group context where relationships are embedded (Chase, 1982b).…”

Evolution of genomic imprinting as a coordinator of coadapted gene expression

“…First, imprinted genes tend to have a clustered distribution in mammalian (15,18,19) and plant genomes (20), with the mammalian clustering appearing to be conserved in vertebrate evolution (21). Second, imprinted genes appear to modulate a limited number of types of traits, with most genes having effects on growth (especially in relation to the demand for maternal provisioning, often via the placenta) and/or behaviors (17,22), with behavioral effects being largely associated with parental and social behaviors (13,(23)(24)(25)(26)(27). Many of the theories for the evolution of genomic imprinting arise from or are strongly tied to this apparently limited range of phenotypes influenced by most imprinted genes.…”