pakulová M., Horák P.,
Dvořák J. (2001): The karyotype of Trichobilharzia regenti Horák, Kolářová et
Dvořák, 1998 (Digenea: Schistosomatidae), a nasal avian schistosome in Central
Europe. Parasitology Research 87 (6): 479-483.
Keywords:
MIXED INFECTIONS, MATING-BEHAVIOR, B-CHROMOSOMES, INTERCALATUM, HAEMATOBIUM,
ORIGIN, SYSTEM
Abstract
The karyotype
of a European bird nasal schistosome, Trichobilharzia regenti Horak, Kolarova
et Dvorak, 1998, was determined. The chromosome set comprises eight pairs, seven
of which are autosomes and one sex pair consisting of ZZ in males and ZW in
females. The Z is the largest chromosome of the set, having a submeta-metacentric
location of centromere, while the W is a small metacentric chromosome. More
than 60% of the analyzed cells originating from both male and female sporocysts
contained one or two small submetacentric supernumerary B chromosomes, occurring
more frequently in female than in male cells. The formula of the karyotype structure
is 2n = 16 + (B), n = 5m + 1sm-m + 1sm + Zsm-m/Wm + (Bsm). The C-banding method
revealed small pericentric heterochromatin blocks in the sex chromosome Z and
all autosomes, except pairs 5 and 6. Satellited pair 5 showed a distinct terminal
band representing the nucleolar organizer. Both the W and B chromosomes contained
conspicuous heterochromatin blocks at the long arm adjacent to the centromere.
The currently described supernumerary chromosomes in T. regenti represent the
first record of B chromosomes within the family Schistosomatidae
ISSN 0932-0113
IF 1,025
USA