Badaeva E D, Friebe B, Zoshchuk S A, Zelenin A V, Gill B S
Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.
Chromosome Res. 1998 Dec;6(8):629-37. doi: 10.1023/a:1009257527391.
The distribution of highly repetitive DNA sequences on chromosomes of tetraploid and hexaploid cytotypes of Aegilops crassa (Dcr1Xcr and Dcr1XcrDcr2 genomes) was studied using C-banding and in situ hybridization analyses with the pSc119, pAs1 and pTa794 DNA clones. In total, 14 tetraploid and five hexaploid accessions were examined. All chromosomes can be identified by their C-banding and ISH pattern with the pAs1 DNA clone. Only a few pSc119 hybridization sites were observed in the telomeric regions of several chromosomes. We found a high level of C-banding polymorphism and only minor variations in labeling patterns. The position of C-bands generally coincided with the location of the pAs1 sequence. Three 5S rDNA loci were detected in tetraploid Ae. crassa, whereas five pTa794 ISH sites were observed in 6x Ae. crassa. All the hexaploid accessions differed from the tetraploids by a reciprocal non-centromeric translocation involving chromosomes A and N. Three additional translocations were detected in the accessions analyzed. The Dcr1 genome of 4x Ae. crassa is highly modified compared with the D genome of the progenitor species Ae. tauschii. Because of the large amount of chromosomal rearrangements, the origin of the Xcr genome remains unknown. The second Dcr2 genome of 6x Ae. crassa is different from the Dcr1 genome but is similar to the D-genome chromosomes of Ae. tauschii, indicating that no additional large rearrangements occurred at the hexaploid level.
利用C带以及pSc119、pAs1和pTa794 DNA克隆的原位杂交分析，研究了粗山羊草四倍体和六倍体细胞型（Dcr1Xcr和Dcr1XcrDcr2基因组）染色体上高度重复DNA序列的分布。总共检测了14份四倍体材料和5份六倍体材料。所有染色体都可通过其C带以及与pAs1 DNA克隆的原位杂交模式进行识别。在几条染色体的端粒区域仅观察到少数pSc119杂交位点。我们发现C带多态性水平较高，而标记模式仅有微小变化。C带的位置通常与pAs1序列的位置一致。在四倍体粗山羊草中检测到3个5S rDNA位点，而在六倍体粗山羊草中观察到5个pTa794原位杂交位点。所有六倍体材料与四倍体材料的差异在于涉及A和N染色体的相互非着丝粒易位。在所分析的材料中还检测到另外3种易位。四倍体粗山羊草的Dcr1基因组与祖先物种节节麦的D基因组相比有高度修饰。由于大量的染色体重排，Xcr基因组的起源仍然未知。六倍体粗山羊草的第二个Dcr2基因组与Dcr1基因组不同，但与节节麦的D基因组染色体相似，这表明在六倍体水平没有发生额外的大规模重排。
