STRUCTURE AND INHERITANCE OF SOME HETEROZYGOUS ROBERTSONIAN TRANSLOCATIONS IN MAN
STRUCTURE AND INHERITANCE OF SOME HETEROZYGOUS ROBERTSONIAN TRANSLOCATIONS IN MAN
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DOI：
10.1136/jmg.13.5.381
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发表时间：
1976-01-01
影响因子：
4
通讯作者：
LAMPOTANG, PRLC
中科院分区：
文献类型：
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作者：
DANIEL, A;LAMPOTANG, PRLC
对25个罗伯逊易位的显带研究表明，所有的易位都可以被解释为稳定的双着丝粒。它们稳定的机制可能是它们的着丝粒接近，但着丝粒抑制也可能起到作用。在许多这些双着丝粒易位中，在C-带制备中观察到不连续的着丝粒抑制，如着丝粒区域中的一个染色单体分离所示。与第一种未明确关系的进一步观察是，在相同的易位类型中，两个构成着丝粒异染色质(CCH)区域与易位的组成染色体的比率是不同的，例如t(13；14)。这一比例可能会影响偏析比。精子发生异常可能是母本杂合子和父本杂合子后代中非整倍体比例不同的可能机制。两个t-(21；21)S都不能解释为等染色体。罗伯逊融合易位可以被定义为稳定的双着丝粒全臂易位，两个着丝粒都在中间位置，导致在形成过程中丢失一个小的无着丝粒片段。它们在端部着丝粒之间或某些端着丝粒染色体之间出现的频率很高，这是因为这些染色体的某些固有性质不属于中部着丝粒染色体，并由着丝粒的间期联合调节。
Banding studies in 25 Robertsonian translocations showed that all could be interpreted as stable dicentrics. The mechanism for their stability is likely to be the proximity of their centromeres but centromeric supression could also have a role. In many of these dicentric translocations, discontinuous centromeric suppression, as indicated by chromatid separation at 1 of the centromeric regions, was observed in C-banded preparations. A further observation of undefined relation to the 1st was that the ratio of the 2 constitutive centromeric heterochromatin (CCH) regions from the component chromosomes of the translocations was variable in the same translocation type, e.g., t(13;14). This ratio may influence the segregation ratio. Abnormal spermatogenesis is suggested as the likely mechanism for the difference in the proportion of aneuploid offspring in the progeny of maternal and paternal heterozygotes. Neither of the t dic(21;21)s could be interpreted as isochromosomes. Robertsonian fusion translocations may be defined as stable, dicentric, whole-arm translocations, with both centromeres in a median position and resulting in the loss of a small acentric fragment during their formation. They occur at high frequency between telocentric or, as in man, certain acrocentric chromosomes because of some intrinsic property of those chromosomes not possessed by metacentric chromosomes and mediated by interphase association of centromeres.