The first complete tree fern chloroplast genome has been successfully determined by the research group led by Professor Ting Wang from Wuhan Botanical Garden, Chinese Academy of Sciences, with the cooperation of Sun Yat-sen University. This research has been published in BMC Evolutionary Biology on the 11th June 2009 entitled “Complete chloroplast genome sequence of a tree fern Alsophila spinulosa: insights into evolutionary changes in fern chloroplast genomes”.

In the paper, Lei Gao et al. first report the entire chloroplast DNA sequence of the scaly tree fern A. spinulosa and then provide a comprehensive chloroplast genomics analysis of ferns. The A. spinulosa chloroplast genome is 156,661 base pairs in length and contains 117 genes encoding 85 proteins, 28 tRNAs as well as 4 rRNAs. Certain particular characteristics have been revealed in the genome. Of them, a unique trnR-UCG gene is found between rbcL and accD, representing a putative molecular apomorphy of tree ferns. A highly repeated 565-bp-region, which is composed of tandem iterations of 11 similar segments, is also observed at one endpoint of an ancient inversion. These results not only present fresh insights into the structure, organization and evolution of chloroplast genomes, but also provide useful data for future phylogenome and adaptive evolution studies of ferns.