Molecular Relationships between Closely Related Species

• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1996
• Subjects: Turbot
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.549.1264; http://faculty.uml.edu/rhochberg/hochberglab/Courses/Parasite/PDF Papers/Cestoda/Bothriocephalus relationships.pdf

DNA/DNA hybridization has been carried out to establish the evolutionary relationships among sev-eral host-specific bothriocephalid tapeworms species (Cestoda: Platyhelminthes). Comparative anatomy is not informative for deciphering the relationships among these sibling morphological taxa, and clearcut genetic differences have previously identified seven biological species which are each highly specific to a single host. We show that two species (Bothriocephalus gregarius and B. renaudii) infesting the same host (turbot: Psetta maxima) in two different geographic areas are not sister-taxa. Moreover, a strong decrease in theamount ofDNAchange is observed inone species of tapeworm, documenting amarked heterogeneity of rates of nucleotidic substitution among these very closely re-lated organisms. Based on these observations, different hypotheses are developed for understanding the evolu-tionary history of this assemblage of parasites, suggest-ing that host-switching has played an important role in the recent past. r 1997 Academic Press