Linares C, Ferrer E, Fominaya A
Department of Cell Biology and Genetics, University of Alcalá, Campus Universitario, ES-28871 Alcalá de Henares, Madrid, Spain.
Proc Natl Acad Sci U S A. 1998 Oct 13;95(21):12450-5. doi: 10.1073/pnas.95.21.12450.
A satellite DNA sequence, As120a, specific to the A-genome chromosomes in the hexaploid oat, Avena sativa L., was isolated by subcloning a fragment with internal tandem repeats from a plasmid, pAs120, that had been obtained from an Avena strigosa (As genome) genomic library. Southern and in situ hybridization showed that sequences with homology to sequences within pAs120 were dispersed throughout the genome of diploid (A and C genomes), tetraploid (AC genomes), and hexaploid (ACD genomes) Avena species. In contrast, sequences homologous to As120a were found in two A-genome species (A. strigosa and Avena longiglumis) and in the hexaploid A. sativa whereas this sequence was little amplified in the tetraploid Avena murphyi and was absent in the remaining A- and C-genome diploid species. In situ hybridization of pAs120a to hexaploid oat species revealed the distribution of elements of the As120a repeated family over both arms of 14 of 42 chromosomes of this species. By using double in situ hybridization with pAs120a and a C genome-specific probe, three sets of 14 chromosomes were revealed corresponding to the A, C, and D genomes of the hexaploid species. Simultaneous in situ hybridizations with pAs120a and ribosomal probes were used to assign the SAT chromosomes of hexaploid species to their correct genomes. This work reports a sequence able to distinguish between the closely related A and D genomes of hexaploid oats. This sequence offers new opportunities to analyze the relationships of Avena species and to explore the possible evolution of various polyploid oat species.
通过从一个从燕麦（As基因组）基因组文库获得的质粒pAs120中，亚克隆一段含有内部串联重复序列的片段，分离出了一个六倍体燕麦（Avena sativa L.）A基因组染色体特有的卫星DNA序列As120a。Southern杂交和原位杂交表明，与pAs120内序列具有同源性的序列分散在二倍体（A和C基因组）、四倍体（AC基因组）和六倍体（ACD基因组）燕麦物种的整个基因组中。相比之下，与As120a同源的序列在两个A基因组物种（燕麦和长颖燕麦）以及六倍体栽培燕麦中被发现，而该序列在四倍体穆氏燕麦中扩增很少，在其余的A和C基因组二倍体物种中不存在。pAs120a与六倍体燕麦物种的原位杂交揭示了As120a重复家族元件在该物种42条染色体中14条染色体的两条臂上的分布。通过使用pAs120a和一个C基因组特异性探针进行双重原位杂交，揭示了对应于六倍体物种A、C和D基因组的三组14条染色体。用pAs120a和核糖体探针同时进行原位杂交，将六倍体物种的随体染色体分配到其正确的基因组中。这项工作报道了一个能够区分六倍体燕麦密切相关的A和D基因组的序列。该序列为分析燕麦物种之间的关系以及探索各种多倍体燕麦物种可能的进化提供了新的机会。
