Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: "Segregational patterns of a chromosome insertion in the progeny of twin chimeric bulls | Génét. Sél. Evol. 1987 19 1 127-132 Note Segregational patterns of a chromosome insertion in the progeny of twin chimeric bulls . MORAES and Margarete s. MATTEVI Instituto José Ghisolfi Faculdades Unidas de Bagé 96400 Bagé RS Brazil Departamento de Genética Universidade Federal do Rio Grande do Sul 90001 Porto Alegre RS Brazil Summary Chromosome studies in 99 offspring of twin bulls know to be leukocyte chimeras for an insertion in chromosome 16 revealed that only one sired heterozygotes carrying the abnormal chromosome. This indicated that the chimerism observed in the leukocytes did not extend to the germ cells. Key words Chimerism leukocytes germ cells ins 16. Resume Modalítés de segregation d une insertion chromosomique dans la descendance de taureaux jumeaux chimériques L etude chromosomique de 99 produits de taureaux jumeaux identifies comme des chimères leucocytaires pour une insertion dans le chromosome 16 a montré que seul un taureau a engendré des heterozygotes portant le chromosome anormal. Ceci montre que le chimérisme observe dans les leucocytes ne sest pas étendu aux cellules germinales. Mots clés Clìimérisme leucocytes cellules germinales ins 16. I. Introduction The insertion in chromosome 16 ins 16 fig. la probably resulted from a centromeric transposition following 3 breaks in the autosome and was observed in leukocyte cultures from 7 out of a total sample of 81 Charolais cattle. The carriers 128 . MORAES Margarete s. MATTEVI included a pair of chimeric twin bulls no. 113 and 112 which respectively presented 11 30 37 p. 100 and 11 15 73 p. 100 of mitotic cells carrying the submetacentric marker chromosome as against cells with a normal karyotype Moraes et al. 1980 . Because of the chimeric nature of the twins and the rarity of the insertion in the population it was concluded that in terms of lymphomyeloid stem cells one twin must have originally been heterozygous for the ins 16 whereas the other twin had a normal karyotype and the mixing
