An international team of researchers has generated the most robust genome to date of the dinoflagellate Symbiodinium microadriaticum, a species involved in a life-supporting symbiosis with corals. While the updated genome confirms some of what has been suggested by previous work, an unusual relationship between DNA transcription and the shape and organization of their chromosomes reveals that dinoflagellates harbor some of the strangest genomes in the eukaryotic world, according to findings published April 29 in Nature Genetics.
Rather than the flexible, X-shaped chromosomes familiar to humans, dinoflagellates organize their genetic material in orderly blocks along rigid, rod-shaped chromosomes. Genes within blocks are consistently transcribed in one direction and rarely interact with others outside their immediate vicinity. This odd arrangement, the authors found, influences the three-dimensional structure of the entire chromosome.