The high resolution GBA + CBA-banded karyotype in cattle (Bos taurus L.)

SUMMARYPeripheral blood cultures were set up to obtain high resolution GBA + CBA banding in cattle prometaphase chromosomes of normal karyotypes and rob (1; 29) carrying karyotypes by using early BrdU incorporation simultaneous to MTX-block, Fifty-nine karyotypes were strictly arranged according to the Reading Conference standard. Chromosome pairs from 24 to 29 were also shown in their RBA- banding paterns to further support the GBA + CBA banding in the same chromosomes, including the most disputed ones (chromosomes 25, 27, 28 and 29), and the inconsistencies in the two international cattle chromosome nomenclatures. Comparisons with cattle and river buffalo standard nomenclatures are reported. This study is our contribution to the construction of a GBA + CBA standard karyotype in cattle

An improved characterization of goat chromosomes by means of G- and R-band comparison.

An improved characterization of goat (Capra hircus, 2n = 60) chromosomes was obtained after a G- and R-banding comparison of the prometaphase chromosomes arranged according to the standard karyotype. GTG-, GBG-, RBG, and RBA-banding made possible construction of G- and R-banded idiograms with a common banding nomenclature. A brief G- and R-banding description of chromosomes 4, 6, 22, 23, 25, 27, 28 and 29 is also given

The high resolution G- and R-banding pattern in chromosomes of river buffalo (Bubalus bubalis L.).

High resolution G- and R-banding patterns in chromosomes of river buffalo (Bubalus bubalis L.) were obtained by using early (G-bands) and late (R-bands) BrdU-incorporation in synchronized cell cultures. To better characterize the river buffalo chromosomes, GTG-, GBG-, and RBG-techniques were used. The total number of bands achieved were 490 (207 G-positive, 207 R-positive, 45 variable, and 31 centromeric regions). Only one common G- and R-banding nomenclature was reported. The number, position and intensity of G bands were highly similar by the structural GTC and the replicating GBG-techniques. However, the replicating G- and R-bands appeared to be more distinct and reproducible than the structural G-bands. Some changes in chromosome nomenclature (chromosomes lp, 2p, 5p, and 21) were made when referred to the cattle homologues

Constitutive heterochromatin distribution in pig (Sus scrofa) chromosomes

Summary Constitutive heterochromatin (HC = C-banding) distribution was studied in pig (Sus 5crofa) chromosomes from 20 animals belonging to Cinta Senese and Calabrese breeds raised in southern Italy. The use of CBG-banding, sequential GBG/CBA-banding and sequential GBGA/g- NOR/CBA-banding techniques allowed more detailed characterization of C-banding patterns in pig chromosomes (SSC). The following features were noticed: (a) all autosomes and the X-chromosome showed centromeric C-positive bands; (b) the entire q-arm and proximal part of the p-arm y chromosome were C-positive: (c) clear interstitial C-positive bands were noticed in SSC1q17, SSC3p14 and SSC16q21; (d) the nucleolus organizer (NO) chromosome 10 showed two distinct HC-blocks very far apart in both arms with large, polymorphic (different size) NORs between the chromosome pair, while NO-chromosome 8 showed only one C-positive band (the smallest) in the q-arms; (e) C-band polymorphism was observed between and within chromosome pairs also in relat..

An improved characterization of horse (Equus caballus, 2n=64) chromosomes by using replicating G and R banding patterns

Abstract Peripheral blood lymphocytes were cultured and treated for early- and late-BrdU incorporation to perform replicating G- and R-banding patterns, respectively. Slides were treated for GBG-, RBA- and RBG-banding techniques. Improved banded karyotypes at early- (350 bands) and pro-metaphase (500 bands) stage were performed and GBG- and RBA-banded prometaphase karyotypes were presented for the first time on this species. All chromosomes, including the small acrocentrics, show clear and distinguishable G- and R-banding patterns. Chromosome identification followed the latest chromosome standard nomenclature (ISCNH 1997). This study is also our contribution to further standard karyotype attempts at the prometaphase stage

Comparative fluorescence in situ hybridization (FISH) mapping of twenty-three endogenous Jaagsiekte sheep retrovirus (enJSRVs) in sheep (Ovis aries) and river buffalo (Bubalus bubalis) chromosomes

Endogenous retroviruses (ERVs) are the remnants of ancient infections of host germline cells, thus representing key tools to study host and viral evolution. Homologous ERV sequences often map at the same genomic locus of different species, indicating that retroviral integration occurred in the genomes of the common ancestors of those species. The genome of domestic sheep (Ovis aries) harbors at least twenty-seven copies of ERVs related to the exogenous and pathogenic Jaagsiekte sheep retrovirus (JSRVs), thus referred to as enJSRVs. Some of these loci are unequally distributed between breeds and individuals of the host species due to polymorphic insertions, thereby representing invaluable tools to trace the evolutionary dynamics of virus populations within their hosts. In this study, we extend the cytogenetic physical maps of sheep and river buffalo by performing fluorescent in situ hybridization (FISH) mapping of twenty-three genetically characterized enJSRVs. Additionally, we report the first comparative FISH mapping of enJSRVs in domestic sheep (2n = 54) and river buffalo (Bubalus bubalis, 2n = 50). Finally, we demonstrate that enJSRV loci are conserved in the homologous chromosomes and chromosome bands of both species. Altogether, our results support the hypothesis that enJSRVs were present in the genomes of both species before they differentiated within the Bovidae family

classical and molecular cytogenetic studies in some cattle breeds

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