Social discrimination by quantitative assessment of immunogenetic similarity

Abstract

Genes of the major histocompatibility complex (MHC) that underlie the adaptive immune system may allow vertebrates to recognize their kin. True kin-recognition genes should produce signalling products to which organisms can respond. Allelic variation in the peptide-binding region (PBR) of MHC molecules determines the pool of peptides that can be presented to trigger an immune response. To examine whether these MHC peptides also might underlie assessments of genetic similarity, we tested whether Xenopus laevis tadpoles socially discriminate between pairs of siblings with which they differed in PBR amino acid sequences. We found that tadpoles (four sibships, n ¼ 854) associated preferentially with siblings with which they were more similar in PBR amino acid sequence. Moreover, the strength of their preference for a conspecific was directly proportional to the sequence similarity between them. Discrimination was graded, and correlated more closely with functional sequence differences encoded by MHC class I and class II alleles than with numbers of shared haplotypes. Our results thus suggest that haplotype analyses may fail to reveal fine-scale behavioural responses to divergence in functionally expressed sequences. We conclude that MHC -PBR gene products mediate quantitative social assessment of immunogenetic similarity that may facilitate kin recognition in vertebrates.

Automated high-throughput measurement of body movements and cardiac activity of Xenopus tropicalis tadpoles

“…Importantly, we used these animals at pre-metamorphic stages with most of the organs and neuronal structures being developed and functional. These animals are capable of performing complex behavior trials and show learning abilities and social interactions [21,22,26,27,42,43]. Such features are mostly not established in embryos thus, favoring the tadpole model for experiments estimating effects on human health.…”

“…A different approach is provided by the multispecies freshwater biomonitor device (LimCo, Germany) that measures animal behavior through spectral analysis of electrical signals caused by animal movements in a test chamber [23]. The EthoVision software (Noldus, Information technology) is a commercial animal tracking software that has been applied for tracking tadpoles of distinct frog species in tanks [24][25][26][27]. Due to the relatively large size of tadpoles, the heart beat rates and buccal pumping rates can be measured by visual examination of the animal or from video recordings [28,29].…”

The Ties That Bind Us

“…Crucially for the notion of identity fusion, we hypothesize that essential components of one's autobiographical self, resulting from significant life events stored in episodic memory and ranging from the formative experiences of childhood to sharing the traumas of front-line warfare, can be perceived as shared with others in a group. We hypothesize that for humans, with our enhanced episodic memory and narrative selves, the "self" template used in phenotypic matching may involve not only cues of facial resemblance and similar major histocompatibility complexes (Villenger and Waldman 2012) but also cues of shared experience and personal essence. The perception that one shares with others' important, self-defining experiences encoded in episodic memory, we argue, produces a powerful sense of psychological kinship.…”

Modeling human neurodevelopmental disorders in theXenopustadpole: from mechanisms to therapeutic targets

“…Electrophysiological techniques have been successfully employed in Xenopus to quantify network connectivity (Pratt and Aizenman, 2007; Li et al, 2009; Pratt and Aizenman, 2009; Straka and Simmers, 2012), synaptic maturation (Wu et al, 1996; Akerman and Cline, 2006; Aizenman and Cline, 2007; Deeg et al, 2009; Khakhalin and Aizenman, 2012), synaptic plasticity (Engert et al, 2002; Mu and Poo, 2006; Pratt et al, 2008; Tsui et al, 2010) and cell intrinsic properties (Aizenman et al, 2003; Pratt and Aizenman, 2007; Winlove and Roberts, 2011). The behaviors controlled by corresponding neural circuits, including several types of escape behaviors (Roberts et al, 2000; Wassersug and Yamashita, 2002; Dong et al, 2009; Sillar and Robertson, 2009), orienting reflexes (Pronych et al, 1996; Simmons et al, 2004; Straka, 2010) and social behaviors (Katz et al, 1981; Villinger and Waldman, 2012), have been well described, and can be experimentally manipulated (Lum et al, 1982; Jamieson and Roberts, 2000; Wassersug and Yamashita, 2002; Simmons et al, 2004; Dong et al, 2009; Straka, 2010). To sum up, these experimental approaches enable developing neural circuits to be examined at the molecular, cellular and behavioral levels – all in the same organism (Fig.…”