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Free keywords:
immunity; major histocompatibility complex; syngathidae; pathogen; gene repertoire
Abstract:
The major histocompatibility complex (MHC)-mediated adaptive immune
system is the hallmark of gnathostome immune defence. Recent work suggests
that cod-like fishes (Gadidae) lack important components of the MHC class II
mediated immunity. Here, we report a putative independent loss of functionality
of this pathway in another species, the pipefish Syngnathus typhle, that
belongs to a distantly related fish family (Syngnathidae). In a deep transcriptome
sequencing approach comprising several independent normalized and
non-normalized expressed sequence tag (EST) libraries with approximately
7.5 108 reads, sequenced with two next generation platforms (454 and Illumina),
we were unable to identify MHC class IIa/b genes as well as genes
encoding associated receptors. Along with the recent findings in cod, our
results suggest that immune systems of the Euteleosts may be more variable
than previously assumed.