渦鞭毛藻類の独特な核ゲノム

抄録

Dinoflagellates are ecologically important, unicellular eukaryotes in aquatic environments. They have unusual, permanently condensed chromosomes and immense nuclear genome sizes. Recent advances in dinoflagellate biology have revealed many novel genomic features.
The first draft genome of the dinoflagellate, Symbiodinium minutum, displays unique and derived characteristics (http://marinegenomics.oist.jp/genomes/gallery). (1) The genome comprises approximately 42,000 protein-coding genes, including highly duplicated genes for regulator-of-chromosome-condensation proteins. One-third of these have eukaryotic orthologs, whereas the others have similarities to those of bacteria. (2) Symbiodinium genes are enriched in spliceosomal introns (average 18.6 introns/gene), in which donor and accepter splice sites are unique. (3) All spliceosomal snRNA genes, spliced-leader genes, and 5S rRNA genes are clustered in the genome. (4) The Symbiodinium genome displays unidirectionally aligned genes throughout the genome, forming a cluster-like gene arrangement. Here I briefly introduce recent advances in dinoflagellate genomics, paying special attention to the genome structures of gene-rich regions.