Natural variability of trace-amine associated receptors in wild meerkats

The study of olfaction as a sensory modality has been relatively neglected in comparison to other sensory cues, particularly in wildlife research. Furthermore, the genetic basis of olfaction remains poorly understood in non-model species. Recently, receptors belonging to trace amine-associated receptor (TAAR) family have been identified, and they exhibit considerable natural diversity and copy number variations across a range of species. As such, they represent a promising avenue for exploring olfactory processes, particularly in conjunction with more established olfactory receptors. In meerkats (Suricata suricatta), olfaction plays a significant role in foraging, social communication and predator defence. However, no prior research has investigated the genetics of meerkat olfaction. In this study, we leveraged the extensive longitudinal dataset from the Kalahari Meerkat Project, using samples from 398 individuals alive between 1996 and 2023, to develop a high-throughput sequencing approach for assessing TAAR diversity in wild meerkats.

A total of nine TAAR-loci were identified in meerkats, with both copy number variations and allelic polymorphisms observed for TAAR6 and TAAR8. Two distinct paralogues of TAAR6 and eleven distinct amino acid alleles across these paralogues were identified. Additionally, three paralogues of TAAR8, containing 14 distinct amino acid alleles, were discovered. Within each paralogue of both TAAR loci, a single allele is present in almost all individuals, while additional alleles show a markedly higher degree of variability in frequency. A similar pattern emerges in the relative abundance of TAAR alleles throughout the course of the study, which spanned more than 20 years. In line with the high prevalence of specific alleles and the considerable number of synonymous nucleotide exchanges, we found evidence for multiple sites under purifying selection in TAAR6 and TAAR8.

This is the first study to examine TAAR diversity in a cooperative breeder. Investigating the genetic basis of olfaction and inter-individual natural variation in TAAR diversity has the potential to expand the toolbox for integrative zoological research. Such insights could help elucidate the genetic underpinnings of behaviour, such as social communication, mate choice, and life-history strategies all in relation to TAAR diversity.