GENETIC DIFFERENCES AMONG NOBLE CRAYFISH (ASTACUS ASTACUS) STOCKS IN FINLAND, SWEDEN AND ESTONIA BASED ON THE ITS1 REGION

DIFFÉRENCES GÉNÉTIQUES ENTRE LE STOCK FINLANDAIS, SUÉDOIS ET ESTONIEN D’ÉCREVISSES À PATTES ROUGES (ASTACUS ASTACUS) BASÉES SUR` LA RÉGION ITS1

¹ Institute of Applied Biotechnology, University of Kuopio, P.O. Box 1627, FIN-70211, Kuopio, Finland.
² Institute of Applied Biotechnology, University of Kuopio, P.O. Box 1627, FIN-70211, Kuopio, Finland. Crayfish Innovation Centre, Salpaus Further Education, Päijänne-Institute, Meijeritie 1, FIN-17200 Vääksy, Finland.
³ Institute of Freshwater Research, National Board of Fisheries, SE-17893, Drottningholm, Sweden.

Received: 23 June 2005
Accepted: 26 January 2006

Abstract

Noble crayfish (Astacus astacus) is indigenous to Finland. The distribution of A. astacus has diminished dramatically during the past century, due to environmental changes, crayfish plague (Aphanomyces astaci) outbreaks and stocking of alien signal crayfish (Pacifastacus leniusculus). Due to an active reintroduction policy and partly due to illegal introductions, the origins of noble crayfish populations are somewhat unknown. For conservation purposes it is essential to know if the populations are autochthonous or if they are a mixture of several different populations. Genetic variation of seven Finnish noble crayfish populations was studied comparing the variation in a short tandem repeat in the rDNA internal transcribed spacer 1 region (ITS1 region). Five Swedish and five Estonian populations were used as reference populations. Based on the ITS1 fragment variation, some of the analysed Finnish noble crayfish populations were most likely original populations or originated from one source population. They differed from the other populations according to the Population Divergence Test. However, there were no differences between some of the Finnish populations and this may be a consequence of multiple stockings. Differences among noble crayfish populations from the three countries were also studied. Five of the Finnish populations differed from the Swedish and the Estonian populations. One population, Lake Saimaa, did not differ from one Estonian and two Swedish populations. Furthermore, a population from northern Finland was not different from a population in northern Sweden. The Estonian populations had a larger number of fragments present in their genotypes compared to the Finnish and the Swedish populations. Private fragments, which were typical to only one country, were found in two Finnish, in four Estonian and in three Swedish populations.

Résumé

L’écrevisse à pattes rouges (Astacus astacus) est une espèce indigène de Finlande. Sa répartition a diminué remarquablement, en raison de changements environnementaux, d’épizooties dues à la peste de l’écrevisse (Aphanomyces astaci) et à l’introduction de l’écrevisse de Californie (Pacifastacus leniusculus). Due à une active politique de réintroductions et partiellement, à des introductions illégales d’écrevisses à pattes rouges, l’origine de ces populations est habituellement non connue. La variation génétique de sept populations finlandaises d’écrevisse à pattes rouges a été étudiée en comparant les variations d’un motif répété dans la région ITS1 de ADN ribosomique nucléaire. Cinq populations suédoises et cinq populations estoniennes ont été utilisées comme référence. Basé sur les variations de la taille du fragment ITS1, nous avons trouvé que la plupart des populations finlandaises étaient génétiquement d’origine. Cependant, il n’y a pas de différence entre certain des populations finlandaises indiquant une similarité génétique entre celles-ci. Cela peut être la conséquence de différents épisodes de translocations entre ces populations. Cinq populations finlandaises sont clairement différentes des populations suédoises et estoniennes mais une, celle du lac Saimaa, est génétiquement proche d’une population estonienne et de trois populations suédoises. De plus, une population du Nord de la Finlande est reliée à une population du Nord de la Suède.