DETECTION OF NONDISJUNCTION AND RECOMBINATION IN MEIOTIC AND POSTMEIOTIC CELLS FROM XY(SXR) [XY,TP(Y)1CT] MICE USING MULTICOLOR FLUORESCENCE IN-SITU HYBRIDIZATION
DETECTION OF NONDISJUNCTION AND RECOMBINATION IN MEIOTIC AND POSTMEIOTIC CELLS FROM XY(SXR) [XY,TP(Y)1CT] MICE USING MULTICOLOR FLUORESCENCE IN-SITU HYBRIDIZATION
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DOI：
10.1073/pnas.91.2.524
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发表时间：
1994-01-18
影响因子：
11.1
通讯作者：
WARD, DC
中科院分区：
文献类型：
--
作者：
ASHLEY, T;RIED, T;WARD, DC
目前的减数分裂学说认为，突触是重组所必需的，重组是适当分离所必需的。小鼠染色体畸变XY(Sxr)[性反转；重新命名为XY， Tp(Y)1Ct]似乎挑战了这一假设，因为尽管染色体X和Y经常不能突触和重组，但非整倍体后代并没有显著增加。对这个难题的一种解释可能是X-Y单价精母细胞无法存活。性别反转的表型是由X染色体和Y染色体之间的“强制性”交叉产生的，这种交叉总是发生在睾丸决定基因Sry的复制副本的近端，并将Y染色体的一个副本转移到X染色体的一个染色单体上。遗传带有Sly基因的X染色体的动物在染色体上是雌性，但在表型上是雄性。我们利用荧光原位杂交（FISH）可视化X和Y染色体、Sry序列和8号染色体的探针，追踪重组和非重组染色体在中期I和中期II进入精细胞和精子的命运。在多色FISH检测的219个配子中，尽管X-Y在中期分离的频率很高（66%），但非整倍体产物（XY或“O”）的频率较低（3.7%），在平衡配子中，X和Y重组染色体略高于非重组染色体。这两个观察结果都支持了早期的建议，即原代精母细胞的asynapysis和不分离导致它们的发育停滞和退化。
Current meiotic dogma holds that synapsis is required for recombination and that recombination is required for proper disjunction. The mouse chromosome aberration XY(Sxr) [sex reversal; redesignated XY, Tp(Y)1Ct] appears to challenge this assumption, for although chromosomes X and Y often fail to synapse and recombine, there is no dramatic increase in aneuploid progeny. An explanation of this conundrum might be that X-Y univalent spermatocytes do not survive. The phenotype of sex reversal is generated by the ''obligatory'' crossover between the X and Y chromosomes, which always occurs proximal to a duplicated copy of the testis determining gene Sry and transfers one copy from one chromatid of the Y chromosome to one chromatid of the X. Animals that inherit an X chromosome with the Sly gene are chromosomally female but phenotypically male. We have used fluorescence in situ hybridization (FISH) to visualize probes for the X and Y chromosomes and for the Sry sequence and chromosome 8 to track the fate of both recombinant and nonrecombinant chromosomes through metaphases I and II into spermatids and sperm. In the 219 gametes examined by multicolor FISH, the frequency of aneuploid products (XY or ''O'') was low (3.7%) despite a high frequency (66%) of X-Y separation at metaphase I, In balanced gametes, X and Y recombinant chromosomes slightly exceeded nonrecombinants. Both of these observations support the earlier proposal that asynapsis and nondisjunction in primary spermatocytes lead to their developmental arrest and degeneration.