An overall presentation of the T cell receptor (TR) genomics in Camelidae: future perspectives through Illumina sequencing in Camelus dromedarius

Here we review the structural characteristics and the current status of the detailed genomic organization of α/ β and γ/δ T cell receptors (TRs) loci in the Camelus genus. We discuss on the organization of loci and chains from γ/δ TR, during the synthesis of which somatic hypermutations occur, a process which is known for an extremely limited number of species for TR. Thanks to identification of the reference (AMPH and STARD3NL) genes in Camelus dromedarius and Camelus ferus, we report the updating of the gamma (TRG) locus discussing evolutionary aspects with respect to human and sheep loci upon the identification of the TRGC5 cassette. We also review the comparative genomics of the T cell receptor beta (TRB) locus starting from the Camelus dromedarius and moving forward through the draft genome sequences of its wild and domestic Bactrian congeners, Camelus ferus and Camelus bactrianus. Therefore, with the aim of investigating the genomic variability of the T cell receptors loci in Camelus dromedarius considered as useful and promising model for therapeutic applications and for phylogenetic studies in the adaptive immune responses, we intend to take advantage of the large-scale project of Illumina genome sequencing. The 2019 Illumina® Agricultural Greater Good Initiative Award is expected to generate hundreds of whole-genome sequences of Camelus dromedarius samples collected from a wide intercontinental geographic range, thus paving the way toward an improved understanding of the genetic architecture of T cell receptors loci and their interindividual diversity.