Köhler M R, Vogt P H
Sektion Molekulare Humangenetik, Universität Heidelberg, Germany.
Chromosoma. 1994 Sep;103(5):324-30. doi: 10.1007/BF00417879.
Cytogenetic analysis of aberrant human Y chromosomes was done by fluorescence in situ hybridization (FISH) with Y specific repetitive DNA probes. It revealed an interstitial deletion of different DNA blocks in two dicentric chromosome structures. One deletion includes the total alphoid DNA structure of one centromeric region. The second deletion includes the total repetitive DYZ5 DNA structure in the pericentromeric region of one short Y arm. Both dicentric Y chromosomes were iso(Yp) chromosomes with break and fusion point located in Yq11, the euchromatic part of the long Y arm. Their phenotypic appearance was "abnormal", resembling small monocentric Yq-chromosomes in metaphase plates. Mosaic cell lines, usually included in karyotypes with dicentric Y chromosomes, were not observed. It is assumed that both deletion events suppress the kinetochore activity in one Y centromeric region and thus stabilize its dicentric structure. Local interstitial deletion events had not been described in dicentric human Y chromosomes, but are common in dicentric yeast chromosomes. This raises the question of whether deletion events in dicentric human chromosomes are rare or restricted to the Y chromosome or also represent a general possibility for stabilization of a dicentric chromosome structure in human.
利用Y特异性重复DNA探针，通过荧光原位杂交（FISH）对异常人类Y染色体进行了细胞遗传学分析。结果显示，在两个双着丝粒染色体结构中存在不同DNA片段的中间缺失。一种缺失包括一个着丝粒区域的全部α卫星DNA结构。另一种缺失包括一条短Y臂着丝粒周围区域的全部重复DYZ5 DNA结构。两条双着丝粒Y染色体均为iso(Yp)染色体，断裂和融合点位于Yq11，即长Y臂的常染色质部分。它们的表型外观“异常”，在中期板中类似于小的单着丝粒Yq染色体。未观察到通常包含在双着丝粒Y染色体核型中的嵌合细胞系。据推测，这两种缺失事件均抑制了一个Y着丝粒区域的动粒活性，从而稳定了其双着丝粒结构。局部中间缺失事件在人类双着丝粒Y染色体中尚未见报道，但在双着丝粒酵母染色体中很常见。这就提出了一个问题，即双着丝粒人类染色体中的缺失事件是罕见的，还是仅限于Y染色体，亦或是人类双着丝粒染色体结构稳定的一种普遍可能性。
