3.1. Phylogenetic analysis of mtCOI gene
Sequence analysis of mtCOI resulted in identification of six alleles present in tested samples and revealed that the haemocyte genome does not correspond to the genome of the host animal in any clams diagnosed with DN, whereas alleles in healthy animals represent the exact same DNA sequence in both sample types. These results are supported by high (>70) bootstrap values (Fig. 3.1 ).
Two mtCOI alleles, ‘a’ and ‘b’, consistent between host tissue and haemolymph within an individual, were identified in healthy clams. Alleles ‘c’, ‘e’, and ‘f’ discovered in solid tissue DNA of neoplastic animals were not found in their haemolymph equivalents. Allele ‘d’ present in haemolymph of neoplastic animals was identical between all four individuals diagnosed with DN and was distinct from both healthy alleles and alleles found in the DNA of hosts with neoplasia. All identified mtCOI alleles are listed in Tab. 3.1 .
3.2. Phylogenetic analysis ofEF1 αgene
Eight EF1α alleles were identified through sequence analysis and cloning with the resulting tree supporting the mtCOI phylogenetic analysis, showing variations between genomes of haemolymph and host tissue in neoplastic clams (Fig. 3.2 ).
EF1α alleles ‘b’, ‘d’, and ‘h’ represent healthy host alleles, as they were found to be identical between both DNA samples from healthyL. balthica individuals. EF1α allele ‘e’ was discovered to be common in haemolymph DNA of all clams diagnosed with DN and was not present or found at a much lower level in normal tissue samples. An additional EF1α ‘g’ allele was detected in haemolymph sample from #158 individual that was not present in the solid tissue of this specimen, although it was found in tissue DNA of another neoplastic clam. Two different alleles, ‘g” and ‘i’, were found in two neoplastic hosts’ DNA (Tab. 3.2 ).