Kovács A, Villagómez D A, Gustavsson I, Lindblad K, Foote R H, Howard T H
Department of Animal Science, Cornell University, Ithaca, NY.
Cytogenet Cell Genet. 1992;61(3):195-201. doi: 10.1159/000133407.
Somatic chromosome analysis of a subfertile Brown Swiss bull demonstrated a three-breakpoint translocation involving chromosomes 1, 8, and 9 in G- and R-banded karyotypes. Based on standard bovine chromosome nomenclature, the translocation was defined as t(1;8;9)(q43;q13;q26). Synaptonemal complex analysis of the chromosome aberration by electron microscopy revealed a hexavalent configuration in 52 of 53 pachytene cells. Twenty-seven cells (51%) had a completely paired hexavalent configuration showing distinctly nonhomologous pairings between normal and/or translocated chromosomes involved in the exchanges. Thirteen cells showed a hexavalent configuration with centrally unpaired chromosome segments but with completely paired terminal arms. In 13 cells (including one at zygotene) the translocation chromosomes formed an open hexavalent, and in one cell there were two completely paired trivalents. Thirty-two cells at diakinesis-MI demonstrated 28 configurations, including one large hexavalent. Testicular histology, testis size, and seminal characteristics were normal.
对一头生育力低下的瑞士褐牛进行体细胞染色体分析，在G带和R带核型中发现了涉及1号、8号和9号染色体的三断点易位。根据标准牛染色体命名法，该易位被定义为t(1;8;9)(q43;q13;q26)。通过电子显微镜对染色体畸变进行联会复合体分析，在53个粗线期细胞中的52个中发现了六价体构型。27个细胞（51%）具有完全配对的六价体构型，显示出参与交换的正常和/或易位染色体之间明显的非同源配对。13个细胞显示六价体构型，中央染色体片段未配对，但末端臂完全配对。在13个细胞（包括一个偶线期细胞）中，易位染色体形成开放的六价体，在一个细胞中有两个完全配对的三价体。32个终变期-减数分裂Ⅰ期细胞显示出28种构型，包括一个大的六价体。睾丸组织学、睾丸大小和精液特征均正常。
