Genetic variability among Fasciola hepatica samples from different host species and geographical localities in Spain revealed by the novel SRAP marker.

A collection of483 samples representing Fasciola from six naturally infected host species and 16 localities in Spain, previously identified morphologically and genetically as Fasciola hepatica, was characterized by a novel genetic marker, namely sequence-related amplified polymorphism (SRAP), aiming to reveal genetic variability within F. hepatica in Spain. Visualization of amplification fragments was carried out on 6% denaturing polyacrylamide gels, followed by staining with 0.1% AgNO3 solution. Ten SRAP primer combinations were tested--six of them turned out to be polymorphic. Thirty-four representative F. hepatica samples from six host species and 16 geographical localities showed polymorphic banding patterns using SRAP primer combinations and were grouped into four major clusters using the unweighted pair-group method with arithmetic averages, indicating the existence of genetic variability within the examined F. hepatica samples. These four clusters were not related to particular host species and/or geographical origins of the samples. The results of the present study revealed that SRAP markers were useful in revealing sufficient polymorphism in F. hepatica samples from Spain and had implications for studying the population genetic structure of the Spanish F. hepatica. To our knowledge, this is the first application of SRAP marker to study genetic variation in parasites of human and animal health significance.