3,010 research outputs found

    classical and molecular cytogenetic studies in some cattle breeds

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    Numerical autosome aberrations have a few importance in the animal breeding since the carriers show generally abnormal body conformation. For this reason, these abnormalities are systematically eliminated from the animal population by the breeders during the animal breeding. Numerical sex chromosome abnormalities are more tolerate by species, since genes are present in single copy (one of two X-chromosome is genetically inactive), and the carriers show usually normal body conformation. For this reason these abnormalities escape the normal breeding selection

    Chromosome fragility in dairy cows exposed to dioxins and dioxin-like PCBs

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    In this study, we compared cross-bred dairy cows in the Susa Valley (Piedmont, northern Italy), reared either near a high-temperature steel production plant (Farms A and B) or in an industry-free area (control). Exposed cows (n 5 36) were selected based on mean bulk milk toxic equivalent values of polychlorodibenzodioxins (PCDDs) and dioxin-like (DL) polychlorobiphenyls (PCBs) and polychlorodi-benzofurans (PCDFs) equal to 18.56 pg/g fat and 8.56 pg/g of fat in dairy cows from Farms A and B, respectively, exceeding both those permitted by the legislation in force (6 pg/g fat PCDDs and DL-PCDFs/PCBs), and those measured in dairy cows (n 5 19) of the farm used as control (1.75 pg/g of fat PCDDs and DL-PCDFs/PCBs). Two types of peripheral blood cell cultures were per-formed: without (normal cultures for the chromosom

    DNA polymerase alpha inhibition by aphidicolin and fragile site expression in prometaphase chromosomes of the Italian Mediterranean River Buffalo (Bubalus bubalis, 2n=50)

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    The present study reports on the expression and localization of "fragile sites" (FS) on prometaphase chromosomes of two groups of river buffaloes (Bubalus bubalis, 2n=50; Mediterranean Italian breed), reared in two different farms, with the aim to characterize chromosome fragility in this species. Totally, 400 aphidicolin induced breakages were identified and localized on the standardized ideogram of the river buffalo karyotype. Preliminary results can be synthesized as follows: (a) aphidicolin showed a remarkable decondensing effect on chromosome structure, enabling further studies at high resolution level; (b) the chromosomal expression of the breakages was not different in the two groups of animals; (c) the most fragile chromosomes were the inactive-X, chromosomes 9, 8 and active-X, showing 42, 32, 31 and 30 breakages, respectively; (d) the breaks were localized in the RBG-negative bands (corresponding to eterochromatic regions) or at the band-interband regions; (e) the chromosomal distribution of the break sites was not random and only partially related to chromosome length. The study is in progress to determine the relative incidence of the fragile sites at chromosomal band level, in order to construct a 'fragile-site map' of river buffalo, which could be utilized for genetic improvement programs of the species
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