Welcome to the Marine Biology Section
Copepod research on the white contintent
On the 22nd of December Eva Werbrouck (PhD) and her supervisor Marleen De Troch left to Buenos Aires. Their final destination was King George Island for an Antarctic research expedition on the impact of temperature on the feeding ecology of harpacticoid copepods (Crustacea).
Exciting times to be a biologist: Sofie's adventures in HCGS!!
Technological developments in DNA sequencing have generated unprecedented possibilities to discover and explore the genome of virtually any organism. The Hubbard Centre for Genome Studies (University of New Hampshire, USA) houses an Illumina Hiseq 2500 sequencer, which generates billions of bp of sequence data. We used this technology to investigate the genomes of four closely related, sympatrically distributed marine nematodes of the Litoditis species complex. These species are morphologically very similar, but experiments have shown that they have distinct responses to salinity and temperature and are attracted to different bacterial strains. We extracted total DNA for each species, which was sheared through ultrasonication. Fragments of ca 500 bp were selected by cutting the appropriate size out of an agarose gel with a razor blade (see picture). Subsequently, these DNA fragments were cleaned and provided with appropriate adaptersequences which allow binding on the flow cell of the Illumina sequencer. These lawns of DNA stretches are flushed with nucleotides (ACGT) and finally generate millions of sequences of 150bp long. All these sequences are then compared to each other, and because they overlap, stretches of several thousands of DNA base pairs can be generated (named contigs). In this way, the genome can be assembled, and gene order, nucleotide substitutions and genome structure can be compared between species. Evidently, bioinformatic pipelines are necessary to handle these huge amounts of data, and several user friendly programs are now being developed. Next generation sequencing will very soon answer questions on how different the genomes of morphologically similar organisms are, which genes are under selection, and how different their pheromone proteins are. In a nutshell, it are exciting times to be a biologist!!
(Posted by Dr. Sofie Derycke)