Two new studies from the lab have been published:
The first is part of Lily’s dissertation and focuses on comparisons of entire organellar genomes and the nuclear rDNA repeat among populations of Tetraplodon fuegianus in the Cape Horn Region: Lewis, L., Y. Liu, R. Rozzi & B. Goffinet. 2016. Infraspecific variation within and across complete organellar genomes and nuclear ribosomal repeats in a moss. Molecular Phylogenetics and Evolution 96: 195–199. doi:10.1016/j.ympev.2015.12.005 pdf Google Scholar
The abstract reads: Bryophytes (mosses, liverworts, and hornworts) are diverse and ecologically and evolutionarily significant yet genome scale data sets and analyses remain extremely sparse relative to other groups of plants, and are completely lacking at the infraspecific level. By sequencing the complete organellar genomes and nuclear ribosomal repeat from seven patches of a South American sub-Antarctic neo-endemic non-model moss, we present the first characterization of infraspecific polymorphism within and across the three genomic compartments for a bryophyte. Diversity within patches is accounted for by both intraindividual and interindividual variation for the nuclear ribosomal repeat and plastid genome, respectively. This represents the most extensive infraspecific genomic dataset generated for an early land plant lineage thus far and provides insight into relative rates of substitution between organellar genomes, including high rates of nonsynonymous to synonymous substitutions.
The other studies is a phylogegraphic analysis of Bryoxiphium, a genus of scattered distribution in the Northern Hemisphere, with disjunct occurrences on Mauritius: Patiño, J., B. Goffinet, M. Sim-Sim & A. Vanderpoorten. 2016. Is the sword moss (Bryoxiphium) a preglacial Tertiary relict? Molecular Phylogenetics and Evolution 96: 200–206. doi:10.1016/j.ympev.2015.12.004 pdf Google Scholar
The abstract reads: The disjunction of floras between East Asia, Southeast North America, West North America, and Southwest Eurasia has been interpreted in terms of the fragmentation of a once continuous mixed mesophytic forest that occurred throughout the Northern Hemisphere due to the climatic and geological changes during the late Tertiary. The sword moss, Bryoxiphium, exhibits a distribution that strikingly resembles that of the mesophytic forest elements such as Liriodendron and is considered as the only living member of an early Tertiary flora in Iceland. These hypotheses are tested here using molecular dating analyses and ancestral area estimations. The results suggest that the extant range of Bryoxiphium results from the fragmentation of a formerly wider range encompassing North America and Southeast Asia about 10 million years ago. The split of continental ancestral populations is too recent to match with a continental drift scenario but is spatially and temporally remarkably congruent with that observed in Tertiary angiosperm relict species. The timing of the colonization of Iceland from Macaronesian ancestors, about two million years ago, is, however, incompatible with the hypothesis that Bryoxiphium is the only living member of an early Tertiary flora of the island. Alaska was recurrently colonized from East Asia. The ability of Bryoxiphium to overcome large oceanic barriers is further evidenced by its occurrence on remote oceanic archipelagos. In particular, Madeira was colonized twice independently from American and East Asian ancestors, respectively. The striking range disjunction of Bryoxiphium is interpreted in terms of its mating system, as the taxon exhibits a very singular pattern of spatial segregation of the sexes.