Molecular identification of traces from the White-tailed Sea Eagle

Over the preceeding decades, after periods of dramatic decline and extinction in many parts of Europe, the White-tailed Sea Eagle (Haliaeetus albicilla) has re-colonized traditional breeding areas. However, this large apex predator remains threatened, not only by the bioaccumulation of environmental pollutants, but also by targeted poisoning and poaching. In connection with a forensic case, a novel PCR assay was developed for the sensitive and specific detection of sea eagle DNA traces in questioned samples of unknown origin.

The assay amplifies a fragment of the popular phylogenetic marker gene cytochrome b. Primers were designed to bind sites with relatively high variability between homologous sequences from H. albicilla and other related European birds of prey.

Assay sensitivity was sufficient for single cell analysis. Specificity was tested in vitro and the primers did not cross-detect DNA from humans, chicken and the following raptors: Common Buzzard (Buteo buteo), Northern Goshawk (Accipiter gentilis), Red Kite (Milvus milvus) and Black Kite (Milvus migrans). Applicability for the analysis of poor quality samples was demonstrated with extracts from field-collected small molted down feathers that did not contain detectable amounts of sea eagle nuclear DNA. Amplicons of the expected size were generated, purified and sequenced. Sequence data were subjected to Basic Local Alignment Search Tool analysis and affiliated with cytochrome b from H. albicilla.

The novel PCR primers allowed for the correct assignment of traces from H. albicilla, even in mixed samples and in cases with limited and degraded biological material.