Peil A, Flachowsky H, Schumann E, Weber W E
Institute of Fruit Breeding, Federal Centre for Breeding Research on Cultivated Plants, D-01326 Dresden, Germany.
Theor Appl Genet. 2003 Jun;107(1):102-9. doi: 10.1007/s00122-003-1212-5. Epub 2003 Feb 20.
In dioecious plants of hemp ( Cannabis sativa L.), males are regarded as heterogametic XY and females as homogametic XX, although it is difficult to discriminate the X cytologically from the Y. The Y chromosome is somewhat larger than the X. Our aim was to analyse AFLP markers on X and Y, and to use them to gain some insight into the structure of the sex chromosomes. Markers located on the sex chromosomes can be grouped into different classes, depending on the presence or absence of a fragment on the X and/or the Y. They are detected by separately analysing male and female progenies of a single cross. Five markers were found to be located on both chromosomes. A few recombinants were observed for marker pairs of this class in the male progenies. Two completely linked markers located on the Y chromosome in the male parent show a recombination rate of r = 0.25 with sex. Recombination must have occurred between the sex chromosomes in the male parent. The recombination analysis led to the conclusion that there is a pseudoautosomal region (PAR) on the sex chromosomes, allowing recombination between the X and the Y chromosome. The other regions of the sex chromosomes show only a few recombination events, for the Y as well as for the X. These results are discussed in comparison to other dioecious plants.
在雌雄异株的大麻（Cannabis sativa L.）中，雄性被视为异配性别的XY型，雌性被视为同配性别的XX型，尽管从细胞学上很难将X染色体与Y染色体区分开来。Y染色体比X染色体稍大一些。我们的目的是分析X和Y染色体上的AFLP标记，并利用它们来深入了解性染色体的结构。根据X染色体和/或Y染色体上是否存在片段，位于性染色体上的标记可分为不同类别。通过分别分析单个杂交组合的雄性和雌性后代来检测这些标记。发现有5个标记位于两条染色体上。在雄性后代中，观察到这类标记对有少数重组情况。位于雄性亲本Y染色体上的两个完全连锁的标记与性别表现出r = 0.25的重组率。雄性亲本的性染色体之间肯定发生了重组。重组分析得出结论，性染色体上存在一个假常染色体区域（PAR），允许X染色体和Y染色体之间发生重组。性染色体的其他区域，无论是Y染色体还是X染色体，都只显示出少数重组事件。将这些结果与其他雌雄异株植物进行了比较讨论。
