Biomedical subjects
Publications and source records attributed to W Jorge.
The karyotype of a male pigmy anteater, Cyclopes didactylus, an endangered species from the Amazon region, is described. The size and morphology of the X and Y chromosomes in mitotic and meiotic analyses is recorded and discussed.
Different cell cycle synchronization methods were used to increase the mitotic index and accuracy of sex determination in murine and bovine embryos. For sexing purposes, colchicine treatment for 2, 4, 6 and 8 h and the FdU-thymidine-colchicine combination were tested in murine embryos. The best results were obtained with colchicine treatment for 8 h (96.88% accuracy) and with FdU-thymidine-colchicine (97.22% accuracy). Mitotic indexes differed significantly between the 2 treatments (21.71% for colchicine and 32.95% for FdU-thymidine-colchicine). For sex identification of murine and bovine demi-embryos, both treatments were demonstrated to be equally effective (nearly 90%). The mitotic index for the FdU-treated murine demi-embryos (19.04%) was higher than the one obtained for the 8-h colchicine treatment (15.62%).
The karyotypes of three additional species of Edentata are described. The differences in karyotype between Tolypeutes matacus (2n = 38), and other species of armadillo is remarkable. Three species of Euphractini were compared through G- and C-banding patterns. Chaetophractus villosus appears to be much closer to Zaedyus pichiy than suggested by taxonomy. On the other hand, Tamandua tetradactyla and Tamandua longicaudata, two different species of anteater, possess the same karyotypes. The presence of an unusual Y-chromosome in Choloepus hoffmanni may be responsible for the peculiar sex-ratio reported in this species.
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An accidental mating between a male eland and a female kudu produced an animal with primarily eland phenotypic characteristics. Despite pronounced male behaviour the animal was azoospermic. Histological examination of the testis showed complete lack of germ cells. Chromosome studies with analysis of Giemsa bands showed that the parental karyotypes differed by two reciprocal translocations and one pericentric inversion, involving chromosomes 1 and 3, 5 and 11, and 9 respectively. All other chromosomes had identical banding patterns.
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