Pupil go to – Ana González


MSc pupil Ana González visited the collections final month as a part of venture NorHydro, the place she spent some weeks within the lab working together with her samples. Right here is an account of her expertise:

The problem of figuring out benthic hydrozoans
Hydrozoa is an interesting however poorly understood group of invertebrates, partly as a result of their identification isn’t at all times a straightforward activity. I’ve been finding out benthic hydrozoan communities for over a 12 months now, specifically these dwelling within the shallow waters of Mallorca (Spain), and I’ve realized that the variety of types and buildings within the group is increased than I had imagined at first of my research, and their identification is tougher than I anticipated. The assemblages of hydrozoans within the Mediterranean are after all very completely different from those that happen in Norway, however one thing that each communities have in frequent is that morphological identification of the animals (i.e. telling which species is current based mostly solely on the traits we will observe) is difficult, which is why one of many goals of my go to to the College Museum of Bergen final December was to study a special method (DNA barcoding) that may assist me enhance the identification of my samples in instances when the morphology of the specimens isn’t adequate.

Among the morphological characters which are used to establish benthic hydrozoans. On the left facet a member of Campanulariidae, with a stolonal colony, and on the fitting facet Monotheca obliqua with an erect colony.

DNA barcoding consists to find a brief DNA sequence (the barcode) that’s comparable for all members of 1 species however completely different from all different species. It’s a comparatively current software that –amongst different issues– has helped the scientific group establish specimens that for one motive or the opposite can’t be recognized based mostly on how they give the impression of being. In some teams, similar to many colonial invertebrates, this system has turn out to be a key asset as a result of the colonies are sometimes too younger or not reproductive, or the essential characters for identifications could also be discovered solely in a single stage of the life cycle and never in others. For this go to I had the prospect to deliver all my samples from Mallorca to Bergen and I set to extracting the DNA of chosen specimens, amplifying two completely different barcode genes (COI and 16S), and acquiring clear sequences for them. I found that, in relation to DNA barcoding, each step of the method is essential, and being affected person and cautious is crucial.

Me on the DNA lab, operating the electrophoresis for my samples.

Getting good leads to the DNA lab relies on a number of components like not forgetting any step and avoiding contamination so far as potential, however the work doesn’t finish there: upon getting your sequences they should be cleaned, quality-checked, and eventually in contrast with others. Which means that having a whole and reliable database of DNA barcodes is important, particularly if you wish to use the sequence that can assist you corroborate the identification of a specimen. When finished proper and with a very good database, the DNA barcodes will be helpful to detect variations between hydrozoan assemblages rising in numerous components of the world or between completely different substrates and ranges of anthropogenic affect, which is what I’m doing in my MSc venture.

Left: Clytia sp rising on the marine plant Posidonia oceanica. Heart: A polyp of Halecium sp, one of the vital troublesome genera of Hydrozoa to establish based mostly solely in morphology, particularly when the colony isn’t reproductive. Proper: Eudendrium sp., present in harbours in Mallorca in excessive abundances.

The evaluation of DNA sequences is a strong software to match specimens of distinct populations and in some instances animals that apparently belong to the identical species grow to be fully completely different (e.g. cryptic species). This isn’t unusual for benthic hydrozoans, which have excessive morphological variety but in addition excessive ranges of plasticity, leading to colonies from completely different species typically being similar to one another after they develop in comparable substrates. As helpful as DNA analyses are, nonetheless, it is usually essential to think about their limitations. For instance, whereas the abundance of every species in a given group is essential to explain the ecological standing of a habitat, estimating abundance continues to be not at all times potential from sequence reads in DNA analyses.

Many cryptic species have been found in Aglaopheniidae because of the mix of DNA barcoding and morphological evaluation

Using DNA barcodes in my work isn’t restricted to my present venture, as I hope my identifications and sequences will assist somewhat bit to enhance the databases for future research of hydrozoan communities within the Mediterranean Sea, and possibly even permit different researchers to match their samples with the species discovered on different components of the world. I believe that wanting carefully at every specimen is the easiest way to really know variation, so each morphology observations and DNA analyses must be mixed to acquire good estimates of the variety of a taxon in any locality. For instance, at any time when the DNA analyses reveal variations in two clades that had been considered the identical species, it’s time to seek for new taxonomic characters that we’d have missed earlier than, and for that motive it is usually essential to have a very good information of the morphology of every species. Each morphological and DNA-based identifications have limitations and benefits so, when you’ve got the chance to make use of each, why select just one?



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