Multiple Alr genes exhibit allorecognition-associated variation in the colonial cnidarian Hydractinia

AbstractThe genetics of allorecognition has been studied extensively in inbred lines ofHydractinia symbiolongicarpus, in which genetic control is attributed mainly to the highly polymorphic lociallorecognition 1 (Alr1) andallorecognition 2 (Alr2), located within the Allorecognition Complex (ARC). While allelic variation atAlr1 andAlr2 can predict the phenotypes in inbred lines, these two loci do not entirely predict the allorecognition phenotypes in wild-type colonies and their progeny, suggesting the presence of additional uncharacterized genes that are involved in the regulation of allorecognition in this species. Comparative genomics analyses were used to identify coding sequence differences from assembled chromosomal intervals of the ARC and from genomic scaffold sequences between two incompatibleH. symbiolongicarpus siblings from a backcross population. New immunoglobulin superfamily (Igsf) genes are reported for the ARC, where five of these genes are closely related to theAlr1 andAlr2 genes, suggesting the presence of multipleAlr-like genes within this complex. Complementary DNA sequence evidence revealed that the allelic polymorphism of eightIgsf genes is associated with allorecognition phenotypes in a backcross population ofH. symbiolongicarpus, yet that association was not found between parental colonies and their offspring. Alternative splicing was found as a mechanism that contributes to the variability of these genes by changing putative activating receptors to in...

Source: Immunogenetics - June 27, 2022 Category: Genetics & Stem Cells Source Type: research