Garrido M A, Jamilena M, Lozano R, Ruiz Rejon C, Ruiz Rejon M, Parker J S
Departamento de Genetica, Facultad de Ciencias, Universidad de Granada, Spain.
Genetica. 1994;94(1):67-71. doi: 10.1007/BF01429221.
Nucleolar-organiser activity has been studied by silver staining and by in situ hybridization with an rDNA probe in two populations of Allium schoenoprasum. One population is monomorphic with NORs and rDNA sites terminal on the short arm of pair 8 in all individuals. The other populations is monomorphic for pair 8 NORs but is also polymorphic for NORs on the long arm of pair 7. All plants in this population carry ribosomal cistrons on both chromosomes of pair 7 but 0, 1 or 2 of these sites can be active in rRNA synthesis. Cis-acting nucleolar-suppression affects the pair 7 locus. We suggest that there has been progressive reduction in the number of NORs during the evolution of A. schoenoprasum.
通过银染以及使用rDNA探针进行原位杂交，对两个葱属植物种群的核仁组织区活性进行了研究。一个种群在所有个体中均为单态，其核仁组织区（NORs）和rDNA位点位于第8对染色体短臂的末端。另一个种群第8对染色体的NORs为单态，但第7对染色体长臂上的NORs也存在多态性。该种群中的所有植物在第7对染色体的两条染色体上均携带核糖体顺反子，但这些位点中0、1或2个可在rRNA合成中发挥活性。顺式作用的核仁抑制影响第7对染色体位点。我们认为，在葱属植物的进化过程中，NORs的数量逐渐减少。
