Supplementary Material for: Characterization of a balanced reciprocal translocation, rcp(9;11)(q27;q11) in cattle

Cytogenetic analysis of a phenotypically normal young bull from Marchigiana breed revealed the presence of an abnormal karyotype. The observation of longer and smaller chromosomes than BTA1 and BTA29, respectively in all metaphases suggested the presence of a reciprocal translocation. RBG-banding confirmed this hypothesis revealing the involvement of BTA9 and BTA11. FISH analyses using cattle-specific BAC clones (474A12 and 293G09 for BTA9; 035D03 for BTA11) identified rcp(9;11)(q27;q11) in the two regions affected. Moreover analyses performed on both parents established the ‘de novo’ origin of the anomaly. Comparison with human homologue sequences (HSA6q24.3→q25.3 for BTA9q27 and HSA2q11.1→q12.1 for BTA11q11) revealed that both breakpoint regions are gene rich as up to date at least 200 genes have been localized in these regions. Thus, further analyses are required to identify the sequences disrupted by the breakpoints and to verify their consequences on rcp carrier phenotype.

对马尔恰纳(Marchigiana)品种的一头表型正常的青年公牛开展细胞遗传学分析时，发现其核型存在异常。在所有分裂中期细胞中观察到，存在一条长于牛常染色体1（BTA1）、一条短于牛常染色体29（BTA29）的染色体，提示存在相互易位。RBG显带技术(RBG-banding)证实了这一推测，结果显示易位涉及BTA9与BTA11。使用牛源细菌人工染色体(Bacterial Artificial Chromosome, BAC)克隆（针对BTA9的474A12和293G09、针对BTA11的035D03）开展荧光原位杂交(Fluorescence In Situ Hybridization, FISH)分析，在两个受影响区域确认了相互易位rcp(9;11)(q27;q11)。此外，对其双亲开展的分析确定该染色体异常为新发（de novo）起源。与人类同源序列（对应BTA9q27的HSA6q24.3→q25.3、对应BTA11q11的HSA2q11.1→q12.1）比对后发现，两个断裂点区域均富含基因——截至当前，这些区域已定位至少200个基因。因此，需开展进一步分析以鉴定断裂点所破坏的序列，并验证其对相互易位携带者表型的影响。