Abstract:
Using high throughput Illumina sequencing technology, we determined complete
sequences for the mitochondrial genome (mitogenome) and nuclear ribosomal DNA
(rDNA) complex for three African freshwater snail taxa within the genus Biomphalaria,
B. pfeifferi, B. sudanica and B. choanomphala, and for two laboratory strains of B.
glabrata originating from the Neotropics. Biomphalaria snails are obligate vectors of the
blood fluke Schistosoma mansoni, a major etiologic agent of human intestinal
schistosomiasis. Our data show that mitogenomes from African and Neotropical
Biomphalaria are highly conserved. With respect to rDNA, the two internal transcribed
spacers (ITS1 and 2) were found to be highly variable whereas the three ribosomal RNA
genes (28S, 5.8S and 18S rRNA) exhibited no or very limited variation. Our analyses
reveal that the two taxa inhabiting Lake Victoria, B. sudanica and B. choanomphala, are
very similar to one another relative to the similarity either shows to B. pfeifferi or B.
glabrata. This new sequence information may prove useful for developing new markers
for snail identification, environmental detection/monitoring purposes or for tracking
epidemiology and snail dependencies of S. mansoni in endemic areas. It also provides
new information pertinent to still unresolved questions in Biomphalaria systematics and
nomenclature.