Distribution of Calanus spp. as determined using a genetic identification system
The morphological similarity of Calanus species necessitates that the only unambiguous way of discriminating between the different species at any developmental stage is with molecular tools. We have developed a simple molecular technique to distinguish between the four species of Calanus copepods fo...
| Published in: | Scientia Marina |
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| Main Authors: | , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Consejo Superior de Investigaciones Científicas
2004
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| Subjects: | |
| Online Access: | https://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/392 https://doi.org/10.3989/scimar.2004.68s1121 |
| Summary: | The morphological similarity of Calanus species necessitates that the only unambiguous way of discriminating between the different species at any developmental stage is with molecular tools. We have developed a simple molecular technique to distinguish between the four species of Calanus copepods found in the North Atlantic (Calanus helgolandicus, C. finmarchicus, C. glacialis and C. hyperboreus) at any life stage. This system involves the PCR amplification of a region of the 16S rRNA gene, followed by Restriction Fragment Length Polymorphism (RFLP) analysis of the amplified product. This paper describes the application of the technique to a number of Calanus samples taken from a wide geographical range within the North Atlantic. Samples were acquired from sites ranging in latitude from the English Channel (50°N) to Tromsø (69°N), including many regions of co-occurrence. A comparison has been made between the distribution of Calanus as determined by molecular techniques and distributions established using traditional morphological identification. The molecular analysis has clearly shown extended areas of distribution and co-occurrence and has confirmed the intraspecific conservation of the restriction sites and therefore the reliability of the technique. La semejanza morfológica de las especies de Calanus obliga a que la única manera clara de discriminar entre las distintas especies en cualquier estadio de desarrollo sea mediante herramientas moleculares. Hemos desarrollado una técnica molecular simple para distinguir las cuatro especies de copépodos del género Calanus que se encuentran en el Atlántico Norte (Calanus helgolandicus, C. finmarchicus, C. glaciales and C. hyperboreus), sea cual sea el estadio de su ciclo biológico. Este sistema implica la amplificación mediante PCR de una región del gen 16S rRNA, seguida de análisis de Polimorfismo de Longitud de Fragmentos de Restricción de (RFLP) del producto amplificado. Este trabajo describe la aplicación de la técnica a varias muestras de Calanus procedentes de una amplia región geográfica en el Atlántico Norte. Se obtuvieron muestras de localidades que iban desde el canal de la Mancha (50°N) a Tromsø (69°N), incluyendo muchas regiones de presencia conjunta. Se ha hecho una comparación entre la distribución de Calanus, determinada por las técnicas moleculares, y las distribuciones sobre la base de la identificación morfológica tradicional. El análisis molecular ha demostrado claramente áreas extendidas de distribución y ocurrencia conjunta y ha confirmado la conservación intraspecífica de los lugares de restricción, con lo que se ha confirmado la fiabilidad de la técnica. |
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