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    Öğe
    Population structure and genetic analysis of narrow-clawed crayfish (Astacus leptodactylus) populations in Turkey
    (Springer, 2014) Akhan, Suleyman; Bektas, Yusuf; Berber, Selcuk; Kalayci, Gokhan
    The genetic differentiation among Turkish populations of the narrow-clawed crayfish was investigated using a partial sequence of cytochrome oxidase subunit I gene (585 bp) of 183 specimens from 17 different crayfish populations. Median joining network and all phylogenetic analyses disclosed a strong haplotype structure with three prominent clades diverged by a range between 20 and 50 mutations and substantial inter-group pairwise sequence divergence (5.19-6.95 %), suggesting the presence of three distinct clades within the Anatolian populations of Astacus leptodactylus. The divergence times among the three clades of Turkish A. leptodactylus are estimated to be 4.96-3.70 Mya using a molecular clock of 1.4 % sequence divergence per million years, pointing to a lower Pliocene separation. The high level of genetic variability (H (d) = 95.8 %, pi = 4.17 %) and numerous private haplotypes suggest the presence of refugial populations in Anatolia unaffected by Pleistocene habitat restrictions. The pattern of genetic variation among Turkish A. leptodactylus populations, therefore, suggests that the unrevealed intraspecific genetic structure is independent of geographic tendency and congruent with the previously reported geographic distribution and number of subspecies (A. l. leptodactylus and A. l. salinus) of A. leptodactylus.
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    Öğe
    Prevalence, molecular identification and genotyping of the crayfish plague pathogen, Aphanomyces astaci in major narrow-clawed crayfish (Pontastacus leptodactylus Eschscholtz, 1823) populations from Türkiye
    (Sciendo, 2024) Akhan, Suleyman; Cagatay, Ifakat Tulay; Berber, Selcuk; Tastan, Busra; Tastan, Yigit; Dalar, Tuba
    Introduction Crayfish plague is considered the most important crayfish disease globally. It is caused by the fungus-like agent, Aphanomyces astaci. This study aimed to identify and determine the prevalence of A. astaci using PCR in narrow-clawed crayfish (Pontastacus leptodactylus) populations from across T & uuml;rkiye.Material and Methods A PCR was carried out with primers specific to the internal transcribed spacer region of the A. astaci pathogen on both telson and abdominal cuticle tissues from crayfish individuals from 41 different locations.Results Aphanomyces astaci was detected in the crayfish from 34 of the locations. Molecular diagnosis showed the prevalence rates of A. astaci to be between 0% and 68.2%. For 7 of the 34 locations, the strain of A. astaci was determined. Microsatellite analysis of tissue from individuals with positive PCR results revealed the A. astaci genotypes in seven populations. Genotype B was found to be the predominant genotype responsible for crayfish plague in Turkish crayfish populations. The Psl genotype (genotype B) was determined in six of the populations, and the As genotype (genotype A) was detected in only one.Conclusion Crayfish plague poses a significant threat to crayfish populations, necessitating the development of rapid, highly sensitive diagnostic methods. An understanding of the sensitivity of the PCR detection method and of the prevalence and genotyping of A. astaci in Turkish crayfish populations has been gained from this study.