The structure and function of "weediness supergene" responsible for the crop-weed complex of pearl millet

珍珠粟（Pennisetum glaucum）是非洲和印度半干旱地区非常重要的粮食作物。西非的珍珠谷子田经常长满长满杂草的珍珠谷子，穗子破碎。我们以前证明了作物型和杂草型珍珠粟之间的差异是由一个基因座决定的。这种名为“杂草”的基因被认为是一种由多个相连基因组成的“超基因”。不幸的是，这个研究项目的主要目标，克隆和破译这个超基因，还没有实现。目前取得的成果有：1)克隆了基于rapd的散装分离分析得到的3个连锁标记带，对其进行测序，并转化为cleaved amplified polymorphic sequence （CAPS）标记。2)对一个分离家系约700个个体进行了AFLP分析。总共有11条与该超基因相关的条带被剪切、克隆并测序。3) 7个非典型表型的个体经多重标记型鉴定为重组体。4)以禾本科珍珠粟为材料构建5倍BAC文库，筛选出2个具有连锁标记的BAC无性系。5)微卫星分析表明，在西非某珍珠粟田，正常作物型珍珠粟的异交率为95%，杂草型珍珠粟的异交率为85%。

Pearl millet (Pennisetum glaucum) is a very important food crop in the semi-arid zones of Africa and India. Pearl millet fields of West Africa are often heavily infested with weedy pearl millet having shattering ears. We previously demonstrated that the difference between crop- and weed-type pearl millet is genetically determined by a single locus. This gene, named weediness, has been supposed to be a "supergene" consisting of linked multiple genes. Unfortunately, the primary objective of this research project, the cloning and decipherring of this supergene, has not yet been achieved.The achievements made so far are :1) Three linked marker bands derived from RAPD-based bulked segregant analysis were cloned, sequenced, and transformed into cleaved amplified polymorphic sequence (CAPS) markers.2) AFLP analysis was performed on a segregating familiy of c. 700 individuals. A total of eleven bands that were shown to be linked to the supergene were cut out, cloned and sequenced.3) Seven individuals with atypical phenotypes were proved to be recombinants based on multiple marker types.4) A 5x BAC library was constructed from the weed type pearl millet, and two BAC clones having the linked markers were selected out.5) A microsatellite analysis demonstrated that the outcrossing rate of pearl millet in a pearl millet field in West Africa was 95% in the normal crop type and 85% in the weed type.