Chadov B F, Chadova E V, Khotskina E A, Kopyl S A, Buzykanova G N
Genetika. 1995 Nov;31(11):1512-20.
A Df(2R)MS2-10 deletion of pericentromeric heterochromatin, an Is(Y;2L)419 insertion of Y material in the region 34A, as well as nondisjunction of chromosomes 2 in 2/F(2L); F(2R) females did not directly prevent chromosome arms in chromosome 2 of Drosophila from pairing. However, these events resulted in (1) two- to four-fold decrease in the rate of crossing-over in chromosome 2;(2) a decreased proportion of exchange tetrads two to three times greater for multiple-exchange tetrads than for single-exchange ones; (3) and a decreased rate of crossing-over throughout the entire chromosome arm enhanced in a proximal direction, An In(l)dl-49+BMl inversion in the X chromosome cancelled the suppression of crossing-over. Crossing-over increased due to an increasing proportion of single-exchange tetrads. The changes in crossing-over found cannot be explained by asynapsis in the chromosomes with rearrangements. According to the authors, these changes are probably accounted for by a delayed pairing of these chromosomes. The delayed pairing of individual chromosome regions or the whole chromosome is considered the most common type of pairing disturbances. Its effect on meiosis are discussed.
2号染色体着丝粒周围异染色质的Df(2R)MS2 - 10缺失、Y染色体物质在34A区域的Is(Y;2L)419插入以及2/F(2L); F(2R)雌性果蝇中2号染色体的不分离，并未直接阻止果蝇2号染色体的染色体臂配对。然而，这些事件导致：(1) 2号染色体的交换率降低了两到四倍；(2) 多交换四分体的交换四分体比例下降，是单交换四分体的两到三倍；(3) 整个染色体臂的交换率降低，并在近端方向增强。X染色体上的In(l)dl - 49 + BMl倒位消除了对交换的抑制。由于单交换四分体比例增加，交换率提高。在有重排的染色体中，观察到的交换变化无法用联会紊乱来解释。作者认为，这些变化可能是由这些染色体的配对延迟所致。单个染色体区域或整个染色体的配对延迟被认为是最常见的配对干扰类型。文中讨论了其对减数分裂的影响。
