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植物远缘杂交和多倍体化中的表观遗传变异   总被引:1,自引:0,他引:1  
植物不同种间乃至属间的天然远缘杂交是经常发生的事件,是新种形成的重要方式,也是人工培育作物新品种的有效手段。但关于杂交导致新种形成的过程和机制一直不清楚。近年来的研究表明,植物发生远缘杂交以及此后的多倍体化过程可以产生大量的、不能用经典遗传规律解释的可遗传变异,其中大部分变异是表观遗传变异(epigenetic variation)。已经发现的杂交及多倍体化诱导产生的表观遗传变异主要是编码基因和转座子DNA甲基化水平和模式的改变,但可以推测与之相关的组蛋白修饰和染色质结构也可能发生变化。目前对此类表观遗传变异的分子机理尚缺乏研究,进一步对植物远缘杂交和多倍体化诱导产生后的表观遗传变异的深入研究将有助于理解这类变异的进化意义及其在作物改良中的更有效的利用。  相似文献   
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Vaccinium elliottii Chapmn., a diploid blueberry in Vacciniumsection Cyanococcus, was crossed with V. arboreum Marsh, a diploid blueberry insection Batodendron. The goal was toproduce hybrids that could be used toincorporate traits from these species intotetraploid southern highbush cultivars. The crosses were made reciprocally usingtwo clones of each species. A recessiveseedling marker gene for anthocyanin-freecotyledons in the V. elliottii clonesused as female parents permitted thetesting of mentor pollination. For thementor pollinations, V. elliottiiplants that were homozygous for therecessive marker allele were pollinatedwith a small amount of viable V.elliottii pollen carrying the recessivemarker mixed with a large amount of V.arboreum pollen carrying the dominantmarker. Thousands of intersectional hybridseedlings were obtained when V.elliottii was the seed parent, both withand without mentor pollination, but nohybrids were obtained from 2735 flowerspollinated in the reciprocal crosses. Theseeds that gave rise to hybrid embryos weresmaller than normal V. elliottiiseeds, but germinated well. Hybridseedlings grew slowly at first, buteventually produced some vigorous plants inthe field, although many plants remainedmuch smaller than normal seedlings of thetwo parental species. Some of the hybridsproduced numerous flowers during the 6years they were observed in the field, buteven with many diploid, tetraploid, andhexaploid section Cyanococcus blueberryplants growing nearby that could haveprovided pollen for their flowers, thehybrids produced no viable seed.  相似文献   
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