Identification of a protochordate histocompatibility gene

We sought to identify the gene underlying fusion/rejection outcomes in Botryllus schlosseri, a colonial protochordate closely related to vertebrates. To do so, we generated RNA-Seq data for 17 colonies with known histocompatibility relationships, and further analyzed B. schlosseri genes with at least 1 mismatch (i.e. polymorphism) between colonies in an exploratory cohort (see below), and sequence coverage for at least 6 fusion pairs and 6 rejection pairs. This filter yielded 7,523 genes. Corresponding RNA-Seq data for these genes are available here, for 17 exploratory colonies, 4 validation colonies, and 2 tissue-specific libraries. Exploratory colonies: P, X, Y, 2362c, Sc32e, 944, 31, 4, 15, Hm9, AA 1, AA 1, AA 3, AA 4, AB, AX, and BB. Validation colonies: Sc109e, Sc6ab, 5606b, and 40. Tissue-specific libraries: vasculature and endostyle.