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Six bovine cosmid-derived microsatellites mapping different syntenic groups are fluorescence in situ hybridization-mapped to six river buffalo chromosomes.
No full textSix bovine cosmid-derived microsatellites (IDVGA53, BTA3/U6; IDVGA61, U13; IDVGA41, BTA12/U27; IDVGA32, BTA15/U19; IDVGA59, BTA26/U26 and IDVGA71, U8), previously assigned to cattle chromosomes, were FISH-mapped to river buffalo chromosomes (BBU) 6q15, 8q34, 13q15, 16q25, 23q22 and 24q13 respectively. Sequential FISH/RBA-banding allowed the precise identification of chromosomes and localization of probe-signals on chromosome bands. These localizations allowed us to assign indirectly, for the first time, six bovine syntenic groups to river buffalo chromosomes, thereby extending its physical map. The localization of IDV-GA71 (bovine U8) to the marker BBU24 adds further information to resolve definitively cattle chromosome ambiguities involving cattle chromosomes 25, 27 and 29
FISH mapping of bovine U21, U1 and U7 molecular markers to river buffalo chromosomes 3p, 5q and 5p.
No full textThree bovine cosmid-derived microsatellites (IDVGA49, IDVGA7 and IDVGA47), previously assigned to cattle syntenic groups U1, U7 and U21, respectively, were fluorescence in situ hybridization (FISH) mapped to river buffalo (Bubalus bubalis, L., 2n = 50) chromosomes (BBU) 3p22 (IDVGA47, U21), BBU 5q21 (IDVGA49, U1) and BBU 5p19 (IDVGA7, U7) using sequential FISH and R-banding techniques. These localizations allowed the assignment, for the first time, of the bovine syntenic groups U21, U1 and U7 to specific river buffalo chromosomes. FISH mapping of IDVGA7 (U7) to cattle rob(1;29) p-arms confirms the banding homologies between BTA 29 and BBU 5p and further supports the idea that cattle standard karyotypes need adjustments
Reproductive disturbances and sex chromosome abnormalities in two female river buffaloes
No full text50,XY gonadal dysgenesis (Swyer's syndrome) in a female river buffalo (Bubalus bubalis)
No full textSex determination in mammals occurs during fertilisation. Generally, the presence of the Y chromosome gives rise to male sex (or male offspring), even when more than one X is present. In human beings, the term '2n=46,XY gonadal dysgenesis (Swyer's syndrome)' is characterised by a 46,XY karyotvpe and incomplete testicular determinations. The lack of a medullary zone in the non-differentiated gonads affects the formation of testicles even when the Y chromosome is present. Many studies have revealed that this sex reversal may be the result of mutations in some Y-specific genes, in particular those of the sex determining region (SRY). In cattle, the most frequent cases of intersex are found in females which are co-twins with males (freemartin syndrome) because of placental anastomoses between the two co-twins. While male co-twins are generally normal, female co-twins are sterile but with normal external features. A few cases of XY intersexes have been reported as gonadal digenesis, true hermaphrodites and pseudohermaphrodites . Sex reversal seems to be much more common in horses, and several cases have been reported. In river buffalo, only two cases of sex chromosome abnormalities have been reported: a female which was trisomic, and a female which was monosomic for X chromosomes. The female which was trisomic was 10 years old and had two births, whereas the monosomic female was four-years-old and sterile. This short communication describes the first case of a female river buffalo 2n=50,XY with
gonadal dysgenesis, otherwise known as Swyer's syndrome. A normally developed five-year-old female river buffalo with reproductive problems, had prominent withers, as in males, a horn base with a circumference of 38 0 cm (26 to 28 cm in normal females), a pubic bone shorter than normal, a normal vagina, a normal vestibule, and a normal clitoris. The buffalo was slaughtered due to its infertility. Subsequent anatomical observation of the reproductive organs revealed slight hypoplasia of derivative Muller's ducts, small cervix uteri, very small gonads with ovary structure, a slight hydrosalpingitis, and a well-developed uteri interhorn ligament. Peripheral blood cultures were performed using two experiments. Cells were left untreated or treated with 5-bromo-2'-deoxyuridine (B3rdU) and bisbenzimize dye (33258; Hoechst) (15 pg/ml each) six hours before harvesting to obtain normal chromosome preparations and chromosomes with R-banded patterns, respectively. Slides obtained from norm3al cultures were treated for CBA-banding as
described by Sumner (1972), and acridine orange staining. Slides treated with BrdU were stained with Giemsa to obtain R13(;-banding. River buLtffalo chromosome identification followed the standard karyotype. Two hundred cells were examined from the tvo cultures, and all showed a male constitution (2n=50,XY), as demonstrated by both CBA-banding and RBG-banding techniques.
Despite external female sex structures (normal vagina, vestibule and clitoris), both the horns (larger than in normal females) and withers (prominent as in males) suggested the action of Y-specific genes affecting the body conformation. However, the absence of testicles caused the lack of Mullerian regression factor production and this justifies the development of Mullerian duct derivatives, even when the Y chromosome was present. This study demonstrates that both breeders and veterinary practitioners should be alert during animal breeding to avoid such problems as retaining females which never produce calves (or milk) on a farm. The female river buffalo in this
study showed some clear male features (horns and withers) which should have suggested earlier cytogenetic investigation
Eight molecular markers from bovine syntenic groups U2, U5, U24, U14, U12, U28, X and Y were fluorescence in situ mapped to eight river buffalo chromosomes
No full textInitial Fluorescence in situ hybridization (FISH) mapping studies in river buffalo assigned three expressed gene loci: BuBu (MHC), IFNT and IFNW (Iannuzzi et al. 1993a,b). Since then, several loci have been FISH mapped in river buffalo in order to extend its physical map by using the cow genetic map as a framework map. One of the most important steps has been the assignment of at least one bovine molecular marker to each river buffalo chromosome or chromosome arm by using bovine probes. Owing to the high degree of homologies in the chromosome banding patterns of cattle and river buffalo (CSKBB, 1994) and homologous gene loci, we were able to indirectly assign several bovine syntenic groups to speci®c river buffalo chromosomes (BBU), confirming the genetic assignments made in river buffalo by somatic cell hybrid mapping procedures (El Nahas et al. 1996). In the present study we FISH mapped eight bovine markers, belonging to eight different syntenic groups, to the corresponding river buffalo chromosomes. Furthermore, as seven of these markers were physically mapped by FISH for the first time in buffalo, we were able to indirectly assign seven bovine syntenic groups to specific chromosomes of buffalo. With these assignments all the river buffalo chromosomes have now at least one marker assigned
Onset of RBA-band replication on the inactive X-chromosomes of cattle (Bos taurus L.), river buffalo (Bubalus bubalis L.) and goat (Capra hircus L.).
No full textMolecular on situ hybridization analysis of sheep and goat Bac clones identifies the transcriptional orientation pf T cell receptor gamma genes on chromosome 4 in bovids
No full textThe T-cell receptor gamma chain combines with the T-cell receptor delta chain to form the heterodimer gamma/delta complex. In human and mouse, gamma/delta T cells amount to less than 5% of the peripheral blood T lymphocytes (‘gamma/delta low species’), whereas in chicken and artiodactyls, gamma/delta T cells amount to about half of the peripheral
blood T cells (‘gamma/delta high species’). Recent studies in bovids have revealed the existence of two paralogous loci TRG1 and TRG2. TRG1 is located on 4q31, within a region of homology with human TRG locus on chromosome 7; while TRG2, localized on 4q15–22, appears to be
unique to these ruminant animals. The entire TRG2 locus is composed of three recombinational units (cassette) named TRG6, TRG2 and TRG4 according to TRGC genes. All TRG cassettes lie in the same transcriptional orientation and are closely spaced. In each ‘V, J, C’ unit, Variable and Joining genes rearrange to be found together spliced to the relevant Constant in mature transcripts. Here, we report the cytological mapping of TRG2 locus on sheep 4q22 unique chromosome band and on homologous chromosome bands of cattle, goat and river buffalo. Moreover molecular characterization of 5' boundaries of sheep TRG2 locus and dual-colour FISH results allowed
us to identify the physical order of the tightly linked TRG2 and HGF loci markers along the chromosome and establish the transcriptional orientation towards the centromere of Variable (V), Joining (J) and Constant (C) TRG2 gene segments on 4q22 band
Increased frequencies of both chromosome abnormalities and SCEs in two sheep flocks exposed to high dioxin levels during pasturage
No full textOnset of RBA-band replication on the inactive X-chromosomes of cattle (Bos taurus L.), river buffalo (Bubalus bubalis L.) and goat (Capra hircus L.).
No full textTwenty-eight loci were comparatively FISH-mapped to sheep (Ovis aries, 2n=54) and river buffalo (Bubalus bubalis,2n=50) chromosomes.
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