Lack of genetic structuring and subspecies differentiation in the capercaillie (Tetrao urogallus) in Finland

Abstract

We sequenced and analysed variation in a 430 bp segment of the mitochondrial DNA control region of 302 Finnish capercaillies Tetrao urogallus. The data were divided into four zones representing the three suggested subspecies (T. u. urogallus, T. u. uralensis/karelicus, T. u. major), and the zone for hybrids between T. u. urogallus and T. u. uralensis. We did not find any clear evidence for different subspecies zones, or for differentiation among local populations. One major haplotype dominated in three zones and comprised 46% of all the sampled birds, and variation among individuals explained 98% of the total variance. Nucleotide and haplotype diversities tended to be high in northern and central parts of the country, whereas lower values were found at the west cost and in eastern parts of the country. Pairwise genetic differences, the low raggedness index, the form of the minimum-spanning network as well as the wide distribution of the most common haplotype supported the model of an expanding population. Hence, the results suggest that the Finnish capercaillie population is - or has been at least very recently - more or less continuous throughout the country.