Cytogenetic analysis of a phenotypically normal young bull from Chianina breed, submitted to a National screening program, revealed the presence of an abnormal chromosome, longer than BTA1. The detection of an oversize chromosome in all metaphases observed associated with a 2n060, XY karyotype, suggested that a reciprocal translocation occurred. In order to verify this hypothesis we performed both RBG-banding on well spread metaphases of the bull and cytogenetic analyses on the parents. Either results confirmed our hypothesis revealing the involvement of BTA5 and BTA6 in a de novo reciprocal translocation rcp(5;6)(q21;q32). Moreover, FISH analyses performed using cattle specific BAC clones (382A08, 711 H05, 414 F05, 661A06 and 995E01 for BTA5; 906 H01, 752C12, 105 H08, 566C11 for BTA6) confirmed also two break-points between 6,1 Mb and 11,2 Mb on BTA5 and between 93,0 Mb and 99,0 Mb on BTA6. At present we are planning to perform further FISH analyses with the aim to narrow the gap of the break-points. Since der(6) is longer than BTA1, it was easily identifiable among other chromosomes by observing metaphases without banding, while der(5) was hidden to the observation. BAC clones 382A08 and 752C12 were very helpful to identify doubtless der(5). Although we can suppose the presence of undiscovered reciprocal translocations in various cattle breed, we are able to identify them only when the derivatives are approximately 15 % longer than BTA1 or 40 % shorter than BTA25. In addition or substitution of banded karyotypes, whole karyotype chromosome painting probes could be applied to all animals submitted to screening programs to reveal the abnormalities which normally escape the cytogenetic investigations performed by using only conventional chromosome staining. In array-CGH analysis (Agilent 244A) using a bovine specific array was also performed to investigate if the translocation was associated with loss or gain of genetic material. The absence of a concomitant deletion or duplication at the break-points allowed us to establish that the translocation was a balanced one.
Molecular and cytogenetic characterization of a new reciprocal translocation in cattle: rcp(5;6)
Iannuzzi L;
2012
Abstract
Cytogenetic analysis of a phenotypically normal young bull from Chianina breed, submitted to a National screening program, revealed the presence of an abnormal chromosome, longer than BTA1. The detection of an oversize chromosome in all metaphases observed associated with a 2n060, XY karyotype, suggested that a reciprocal translocation occurred. In order to verify this hypothesis we performed both RBG-banding on well spread metaphases of the bull and cytogenetic analyses on the parents. Either results confirmed our hypothesis revealing the involvement of BTA5 and BTA6 in a de novo reciprocal translocation rcp(5;6)(q21;q32). Moreover, FISH analyses performed using cattle specific BAC clones (382A08, 711 H05, 414 F05, 661A06 and 995E01 for BTA5; 906 H01, 752C12, 105 H08, 566C11 for BTA6) confirmed also two break-points between 6,1 Mb and 11,2 Mb on BTA5 and between 93,0 Mb and 99,0 Mb on BTA6. At present we are planning to perform further FISH analyses with the aim to narrow the gap of the break-points. Since der(6) is longer than BTA1, it was easily identifiable among other chromosomes by observing metaphases without banding, while der(5) was hidden to the observation. BAC clones 382A08 and 752C12 were very helpful to identify doubtless der(5). Although we can suppose the presence of undiscovered reciprocal translocations in various cattle breed, we are able to identify them only when the derivatives are approximately 15 % longer than BTA1 or 40 % shorter than BTA25. In addition or substitution of banded karyotypes, whole karyotype chromosome painting probes could be applied to all animals submitted to screening programs to reveal the abnormalities which normally escape the cytogenetic investigations performed by using only conventional chromosome staining. In array-CGH analysis (Agilent 244A) using a bovine specific array was also performed to investigate if the translocation was associated with loss or gain of genetic material. The absence of a concomitant deletion or duplication at the break-points allowed us to establish that the translocation was a balanced one.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
