Species proved phylogenetically closer to any other species or strain the tures by freeze avoidance

While an increasingly detailed molecular picture is emerging of cryoprotective dehydration using large scale gene expression and proteomic approaches, no comparable molecular work has been undertaken on the survival of intracellular freezing. With the sea change in current sequencing technology, what was previously R428 structure termed a non-model organism can now become, with a concerted effort and a fraction of the resources that were required even five years ago, a molecular model for a specific physiological trait, which is a powerful change in the way biological systems can now be studied. With this in mind, we have undertaken to sequence not just the transcriptome, which will provide a backbone for expression studies, but also the genome. With the dramatic decrease in cost associated with sequencing genomes, the scaffolds and contigs resulting from a preliminary assembly, even when broken up, are a natural complement to the transcriptome, providing valuable information on gene structure such as intron-exon junctions. To date our only knowledge of the genome comes from a paper by Goldstein and Wharton describing seven synaptonemal complexes, therefore seven chromosome pairs. The molecular information provided on the scale such as the present study, opens up the exploratory possibilities of gene expression studies. But in order to gain more direct evidence for any such exploratory results, it would be valuable to know whether P. davidi is potentially susceptible to functional genetic methodologies. Since Fire et al. determined the role of RNA interference in C. elegans, this method has provided a clear mechanism by which the role of a pathway or specific genes may be understood, for example, in an organism’s response to environmental stresses. With the two sources of information, the transcripts and their gene structure determined by the genomic sequence, clean RNAi probes for specific targets can be easily developed. Recently, Panagrolaimus superbus was shown to respond to feeding RNAi, but a lesson has already been learnt from C. briggsae when, unlike C. elegans for whom it has been a comparative model, it was shown that RNAi was not possible owing to a divergent form of sid-2. A final word on a mystery that has unfolded in the last few years. In 2009, Lewis et al. published a paper on the phylogenetics of the Panagrolaimus genus. P. davidi was included in this study, but unexpectedly.

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