Project description:High group animals with supercooling point (SCP) above -15°C and selected low group animals with SCP below -15°C were prepared from Cryptopygus antarcticus collected from wet moss (Sanionia uncinata (Hedw.)) during the austral summer of 2005 at the British Antarctic Survey's research station at Rothera Point, Adelaide Island (67'34'S, 66'8'W).
Project description:Copy number variations are widespread in eukaryotes. The unusual genome architecture of ciliates, in particular, with its process of amitosis in macronuclear division, provides a valuable model in which to study copy number variation. The current model of amitosis envisions stochastic distribution of macronuclear chromosomes during asexual reproduction. This suggests that amitosis is likely to result in high levels of copy number variation in ciliates, as dividing daughter cells can have variable copy numbers of chromosomes if chromosomal distribution during amitosis is a stochastic process. We examined chromosomal distribution during amitosis in Chilodonella uncinata, a ciliate with gene-size macronuclear chromosomes. We quantified 4 chromosomes in evolving populations of C. uncinata and modeled the amitotic distribution process. We found that macronuclear chromosomes differ in copy number from one another but that copy number does not change as expected under a stochastic process. The chromosome carrying SSU increased in copy number, which is consistent with selection to increase abundance; however, two other studied chromosomes displayed much lower than expected among-line variance. Our models suggest that balancing selection is sufficient to explain the observed maintenance of chromosome copy during asexual reproduction.
Project description:This experiment probed for the presence of known Arabidopsis and rice microRNAs in total RNA samples derived from species representative of the major groups of land plants: Eudicots (Arabidopsis thaliana, Nicotiana benthamiana), monocots (Oryza satica, Triticum aestivum), magnoliids (Liriodendron tulipifera), gymnosperms (Pinus resinosa), ferns (Ceratopteris thalictroides), lycopods (Selaginella uncinata), and mosses (Polytrichum juniperinum). In most cases two technical or biological replicates were performed.
Project description:Organellar genomes of bryophytes are poorly represented with chloroplast genomes of only four mosses, four liverworts and two hornworts having been sequenced and annotated. Moreover, while Antarctic vegetation is dominated by the bryophytes, there are few reports on the plastid genomes for the Antarctic bryophytes. Sanionia uncinata (Hedw.) Loeske is one of the most dominant moss species in the maritime Antarctic. It has been researched as an important marker for ecological studies and as an extremophile plant for studies on stress tolerance. Here, we report the complete plastome sequence of S. uncinata, which can be exploited in comparative studies to identify the lineage-specific divergence across different species. The complete plastome of S. uncinata is 124,374 bp in length with a typical quadripartite structure of 114 unique genes including 82 unique protein-coding genes, 37 tRNA genes and four rRNA genes. However, two genes encoding the α subunit of RNA polymerase (rpoA) and encoding the cytochrome b6/f complex subunit VIII (petN) were absent. We could identify nuclear genes homologous to those genes, which suggests that rpoA and petN might have been relocated from the chloroplast genome to the nuclear genome.