Publication: Chromosomal differentiation of the Schistosoma japonicum complex
Issued Date
2000-04-01
Resource Type
ISSN
00207519
Other identifier(s)
2-s2.0-20244365768
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Mahidol University
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SCOPUS
Bibliographic Citation
International Journal for Parasitology. Vol.30, No.4 (2000), 441-452
Suggested Citation
H. Hirai, T. Taguchi, Y. Saitoh, M. Kawanaka, H. Sugiyama, S. Habe, M. Okamoto, M. Hirata, M. Shimada, W. U. Tiu, K. Lai, E. S. Upatham, T. Agatsuma Chromosomal differentiation of the Schistosoma japonicum complex. International Journal for Parasitology. Vol.30, No.4 (2000), 441-452. doi:10.1016/S0020-7519(99)00186-1 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/25987
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Title
Chromosomal differentiation of the Schistosoma japonicum complex
Abstract
The C-banding pattern, location of telomere sequence and chiasma frequency of four species of the Schistosoma japonicum complex were compared with those of two African species, Schistosoma mansoni and Schistosoma haematobium. In the six species, C-banding patterns of seven autosomes and the two sex chromosomes (Z and W) showed relatively species-specific and geographical (Asian and African) differences. Particularly, a plausible pathway of alteration of chromosome 2 revealed a direction from the A-chromosome to the M- chromosome in terms of rearrangements of pericentric inversion and elimination of constitutive heterochromatin (AM inversion). This chromosome change suggested hypothetically that the S. japonicum complex is the original type, and the African species represents the derived type. Moreover, the mosaic construct of the Asian and African types in Schistosoma sinensium chromosomes prompted us to propose that the species might have been formed by hybrid speciation of the genomes of Asian and African species. Localisation of telomeric repeats enabled Asian and African schistosomes to be distinguished clearly by simple terminal location and by terminal and interstitial locations, respectively. Change of chiasma frequency in the S. japonicum complex might be caused by the reduction of interstitial chiasmate (Xi) in the larger chromosomes, 1 and Z (or W), and the change seems to have progressed to Japan from South East Asia. These data enabled us to predict a tentative evolutionary pathway of schistosomes at the cytogenetic level. Copyright (C) 2000 Australian Society for Parasitology Inc.