Markova Michaela, Lengerova Martina, Zluvova Jitka, Janousek Bohuslav, Vyskot Boris
Laboratory of Plant Developmental Genetics, Institute of Biophysics, Academy of Sciences of the Czech Republic, Kralovopolska 135, CZ-61265 Brno, Czech Republic.
Genome. 2006 Apr;49(4):373-9. doi: 10.1139/g05-112.
The genus Silene is a good model for studying evolution of the sex chromosomes, since it includes species that are hermaphroditic and dioecious, while maintain a basic chromosome number of 2n = 24. For some combinations of Silene species it is possible to construct interspecific hybrids. Here, we present a detailed karyological analysis of a hybrid between the dioecious Silene latifolia as the maternal plant and a related species, hermaphroditic Silene viscosa, used as a pollen partner. Using genomic probes (the genomic in situ hybridization (GISH) technique), we were able to clearly discriminate parental genomes and to show that they are largely separated in distinct nuclear domains. Molecular GISH and fluorescence in situ hybridization (FISH) markers document that the hybrid genome of somatic cells was strictly additive and stable, and that it had 12 chromosomes originating from each parent, including the only X chromosome of S. latifolia. Meiotic analysis revealed that, although related, respective parental chromosomes did not pair or paired only partially, which resulted in frequent chromosome abnormalities such as bridges and irregular non-disjunctions. GISH and FISH markers clearly document that the larger genome of S. latifolia and its largest chromosome component, the X chromosome, were mostly employed in chromosome lagging and misdivision.
麦瓶草属是研究性染色体进化的良好模型，因为它包括雌雄同体和雌雄异株的物种，同时保持基本染色体数2n = 24。对于麦瓶草属物种的某些组合，有可能构建种间杂种。在这里，我们对以雌雄异株的宽叶麦瓶草为母本植物、以相关物种雌雄同体的粘毛麦瓶草为花粉亲本的杂种进行了详细的核型分析。使用基因组探针（基因组原位杂交（GISH）技术），我们能够清楚地区分亲本基因组，并表明它们在不同的核区域中基本分离。分子GISH和荧光原位杂交（FISH）标记证明，体细胞的杂种基因组是严格相加且稳定的，并且它有12条染色体分别来自每个亲本，包括宽叶麦瓶草唯一的X染色体。减数分裂分析表明，尽管亲本染色体相关，但它们各自并不配对或仅部分配对，这导致了频繁的染色体异常，如染色体桥和不规则的不分离。GISH和FISH标记清楚地证明，宽叶麦瓶草较大的基因组及其最大的染色体成分X染色体，大多用于染色体滞后和错分。
