Ný rannsóknaraðferð: umhverfiserfðaefni og fiskirannsóknir / Forensic science method used in fisheries research: environmental DNA

[in english below]

Við vitum öll hvernig erfðasýni af vettvangi glæps eru notuð til að sanna sekt þess sem glæpinn framdi. Allar lífverur losa sífellt húðfrumur og hár í umhverfið. Því er hægt að nota erfasýni til að rannsaka fleira en glæpi eins og útbreiðslu og magn lífvera. Fyrir um áratug var byrjað að mæla erfðaefni  í umhverfinu til að rannsaka úrbreiðslu lífvera í ferskvatni þegar Ficetola og samstarfsfólk síaði vatn úr tjörnum í Frakklandi til að mæla útbreiðslu froska (Ficetola et al., 2008). Fyrsta rannsóknin í sjó var birt 2012 þegar Thomsen og samstarfsmenn notuðu umhverfiserfðaefni til að greina 15 fiskitegundir og 4 fuglategundir á grunnsævi við Elisinore í Danmörku (Thomsen et al., 2012).

Síðan þá hefur verið hröð þróun í notun umhverfiserfðaefnis við rannsóknir á lífríkinu í sjónum. Umhverfiserfðaefni hefur meðal annars verið notað til að rannsaka árstíðarbundna göngur fiska í Hudsonánni í New York (Stoeckle et al., 2017), rannsaka tegundasamsetningu fiska á landgrunnsbrúninni suðvestur af Grænlandi (Thomsen et al., 2016), til að greina lífríkissamsetningu í þaraskógum í Monterey  flóa í Bandaríkjunum (Port et al., 2016) og til að meta stofnstærð hákarlastofna í suðvestur Kyrrahafi (Boussarie et al., 2018).

Við erum að safna umhverfiserfðaefni í fyrsta skipti í þessum leiðangri. Sýnum er safnað fyrir tilraunaverkefni þar sem greina á tegundasamsetningu uppsjávarlífríkis í hafinu umhverfis Ísland. Sýnum verður safnað á 26 stöðvum. Á hverri stöð er síaður 1 lítir af sjó af 5 mismunandi dýpum: yfirborð, 20m, 50m, 200m og 500m. Verkefninu er stjórnað af samstarfsmanni okkar á Hafrannsóknastofnum, Dr. Christophe Pampoulie. Við bíðum spennt eftir að sjá niðurstöðurnar.

Vinsamlegast smellið á myndir til að sjá skýringar.

DNA profiling is a fundamental forensic science method.The murder trial of O. J. Simpson in 1995 introduced DNA use to the public. A tiny fraction of DNA shed from a human as hair or skin cell links an individual to a crime scene. As all TV watchers know, DNA profiling contributes to solving majority of crimes in police shows, and in reality. It is less well known that DNA is being used to measure presence and abundance of organisms in the ocean.

All life in the ocean shed DNA into water in the form of cells or excretion. This is called environmental DNA (eDNA for short) and is extracted from the ocean by filtering seawater.  In the laboratory, eDNA barcoding identifies the DNA to species using cell material caught in the filter.

eDNA barcoding is a new research method in biological sciences. The first scientific paper using eDNA to measure animal presence in water was published in 2008 by Ficetola et al., and mapped distribution of frogs in ponds in France. Thomsen et al. (2012) was the first to apply eDNA to the ocean when he identified 15 fish species and 4 bird species in shallow waters of Elsinore, Denmark.

Since then use of eDNA barcoding has expanded to many branches of marine research, mostly focusing on management and conservation of marine fauna. Recent studies include tracking seasonal fish migrations in Hudson river in New York (Stoeckle et al. 2017), investigate polar and deepwater fish fauna on the continental slope southwest of Greenland (Thomsen et al., 2016), identifying marine fauna in a kelp forest in Monterey Bay, USA (Port et al., 2016), and estimate shark populations in South West Pacific (Boussarie et al., 2018).

eDNA is a non-invasive and relatively cheap research method compared to traditional trawl surveys on research vessels or scuba diving in shallow waters. It is specifically useful to research rare or endangered species as no individuals need to be caught. However, large amount of preparation DNA work is needed to make the DNA barcodes. The eDNA results also need to be ground truth by comparing them to results from traditional research methods such as trawl catches.

Collecting eDNA is one of the new projects on our survey this year. We will sample eDNA at 26 stations in waters all around Iceland. The sampling is for a pilot research project lead by our co-worker Dr. Christophe Pampoulie. This is first attempt to use eDNA barcoding to research marine faune in Icelandic waters. We are excited to see the results.

Please, click on pictures for explanations.

Ritskrá / References:
-Boussarie, G., Judith Bakker, J., Wangensteen, O.S., Mariani, S., Bonnin, L., Juhel, J.-B., Kiszka, J.J., Kulbicki, M., Manel, S., Robbins, W.D., Vigliola, L., and David Mouillot, D. 2018. Environmental DNA illuminates the dark diversity of sharks. Science Advances  02 May 2018: 4, eaap9661. DOI: 10.1126/sciadv.aap9661.
-Ficetola, G.F., Miaud, C., Pompanon, F. & Taberlet, P. (2008) Species detection using environmental DNA from water samples. Biology Letters, 4, 423–425.
-Port JA, O'Donnell JL, Romero-Maraccini OC, Leary PR, Litvin SY, Nickols KJ, et al. Assessing vertebrate biodiversity in a kelp forest ecosystem using environmental DNA. Mol Ecol. 2016;25: 527–541. pmid:26586544
-Stoeckle MY, Soboleva L, Charlop-Powers Z (2017) Aquatic environmental DNA detects seasonal fish abundance and habitat
preference in an urban estuary. PLoS ONE 12(4): e0175186. https://doi.org/10.1371/journal.pone.0175186
-Thomsen PF, Kielgast J, Iversen LL, Møller PR, Rasmussen M, et al. (2012) Detection of a Diverse Marine Fish Fauna Using Environmental DNA from Seawater Samples. PLoS ONE 7(8): e41732. doi:10.1371/journal.pone.0041732
-Thomsen PF, Møller PR, Sigsgaard EE, Knudsen SW, Jørgensen OA, Willerslev E (2016) Environmental DNA from Seawater Samples Correlate with Trawl Catches of Subarctic, Deepwater Fishes. PLoS ONE 11(11): e0165252.doi:10.1371/ journal.pone.0165252
Advertisements