The Plastid Genome of Cladophorales Green Algae is Encoded by Hairpin Chromosomes

Our recent publication "The Plastid Genome of Cladophorales Green Algae is Encoded by Hairpin Chromosomes" is finally online.

All photosynthetic organisms have plastids, and plastid genomes are usually large circular DNA molecules. We have discovered a peculiar and unique chloroplast genome in an important group of green seaweeds, the Cladophorales. Rather than being a large circular molecule, the plastid genome of Cladophorales is fragmented into several small DNA molecules. Each of these single-stranded DNA molecules folds onto itself to form distinct chromosomes, which we named "hairpin chromosomes". Most of the genes normally encoded in the plastid genome of green seaweeds have been transferred to the nucleus of Cladophorales. The presence of abundant retrotransposons in the plastid DNA of Cladophorales hints these mobile elements could be involved in genome fragmentation and gene transfer from the plastid to the nucleus.

Our results present the first evidence that an entire functional organellar genome is encoded by single-stranded DNA molecules, and they will help understand processes driving organellar genome fragmentation, gene transfer between organelles and the minimal set of genes required for a functional plastid.

I am very happy that our hard work resulted in this meravellaus pubblication. Thanks to all the co-authors (Frederik Leliaert, Kenny A. Bogaert, Monique Turmel, Christian Boedeker, Jan Janou?kovec, Juan M. Lopez-Bautista, Heroen Verbruggen, Klaas Vandepoele, and Olivier De Clerck) and all the people that contributed during the years to this achievement.

? Picture: Frederik Leliaert