Department of Applied Biology, University of Perugia, Borgo XX Giugno, 06100 Perugia, Italy.
Genome. 2013 Mar;56(3):155-9. doi: 10.1139/gen-2013-0045. Epub 2013 Mar 18.
The European hazelnut (Corylus avellana L.) is widespread in Europe, where it has been cultivated for centuries. Despite progress in genetics, most of the cytogenetic aspects of this species have been overlooked. The aim of this study was to fill in this gap and obtain basic information on the chromosome structure of this species. Karyomorphological analysis confirmed the chromosome number 2n = 22 and showed that, despite their apparent uniformity, the chromosomes could be separated into three groups of different size: large (L), medium (M), and small (S). As a first step towards the physical mapping of the hazelnut chromosomes, we applied FISH to localize the position of rRNA genes (rDNA). The sites of 45S and 5S rDNA enabled us to identify two chromosome pairs belonging, respectively, to the L and S groups. The self-GISH procedure revealed that repetitive DNA is concentrated in the pericentromeric regions of the chromosomes, as with other species with rather small genomes. The analysis of 5S rDNA repeats offered additional information on the hazelnut genome by obtaining the whole sequence of the transcribed region so far unpublished. The overall results constitute a substantial advance in hazelnut cytogenetics. Further investigation of other species of Corylus could be an effective approach to understanding the phylogenesis of the genus and resolving taxonomic problems.
欧洲榛（Corylus avellana L.）广泛分布于欧洲，在那里已经种植了几个世纪。尽管遗传学取得了进展，但该物种的大多数细胞遗传学方面仍被忽视。本研究旨在填补这一空白，获得该物种染色体结构的基本信息。核型分析证实了染色体数目为 2n=22，并表明，尽管它们的形态看似均匀，但染色体可以分为三组不同大小：大（L）、中（M）和小（S）。作为榛子染色体物理图谱绘制的第一步，我们应用 FISH 定位 rRNA 基因（rDNA）的位置。45S 和 5S rDNA 的位点使我们能够识别分别属于 L 和 S 组的两对染色体。自 GISH 程序显示，重复 DNA 集中在染色体的着丝粒区域，与其他基因组较小的物种一样。5S rDNA 重复序列的分析通过获得迄今为止未公布的转录区域的整个序列，为榛子基因组提供了额外的信息。总体结果是榛子细胞遗传学的重大进展。对其他榛属物种的进一步研究可能是了解该属的系统发生和解决分类学问题的有效方法。
