Comparative Genome Analyses Reveal Distinct Structure in the Saltwater Crocodile MHC

摘要: The major histocompatibility complex (MHC) is a dynamic genome region with an essential role in the adaptive immunity of vertebrates, especially antigen presentation. MHC generally divided into subregions (classes I, II and III) containing genes similar function across species, but different gene number organisation. Crocodylia (crocodilians) are widely distributed represent evolutionary distinct group among higher genomic organisation within this lineage has been largely unexplored. Here, we studied saltwater crocodile (Crocodylus porosus) compared it that other taxa. We characterised clusters encompassing class I based on sequencing bacterial artificial chromosomes. Six spanning ∼452 kb were identified to contain nine genes, six three TAP TRIM gene. These separate scaffold regions greater length (2-6 times longer) than their counterparts well-studied fowl B loci, suggesting compaction avian occurred after crocodilian-avian split. Comparative analyses between from alligator gharial showed large syntenic areas (>80% identity) order. Comparisons vertebrates had located along TAP, consistent birds studied. Linkage TRIM39 observed resembled eutherians compared, absent MHC, appears have intermediate these two lineages. observations suggest structure crocodilians, can help determine was present ancestors archosaurs.