Chromosome landmarks as tools to study the genome of Arabidopsis thaliana.

The model plant Arabidopsis thaliana has long been used for genetic, cellular and molecular studies. Whereas this plant was used as a model of genetics in the 1940's, the first cytogenetic observation of A. thaliana chromosomes was published in the beginning of the 20th century. Although Arabidopsis was not originally considered to be a good plant model for cytogenetics due to smallness of its genome, the number of published chromosome studies has expanded enormously in recent years. The advent of fluorescence in situ hybridization techniques on meiotic chromosomes together with indirect immuno-fluorescence localization of key chromosomal and nuclear proteins and wide accessibility of Arabidopsis mutants have resulted in a synergistic boost in Arabidopsis cytogenetics. In comparison to other plant species, the small genome with under-represented DNA repeats together with a small number of chromosomes makes this model plant easy to comprehend for a cytologist.

Siroky J 《-》

An overview of plant chromosome structure.

Gill N ，Hans CS ，Jackson S 《-》

Cytogenetic analyses of Arabidopsis.

For a long time, Arabidopsis thaliana was not a favorite of cytogeneticists because of its small chromosomes. Nevertheless, most cytogenetic approaches have become applicable to this model plant during the past decade. Recently, the very small genome, the low content, and strong clustering of repetitive sequences even turned out to be advantageous for the first establishment of chromosome painting in a euploid plant. Chromosome painting together with the high-resolution fluorescence in situ hybridization (FISH) mapping on Arabidopsis pachytene chromosomes has opened new perspectives for plant cytogenetics. In this chapter, we describe standard cytogenetic methods including preparation of chromosomes and chromatin fibers, isolation of interphase nuclei, FISH and immunostaining, painting of Arabidopsis chromosomes, and comparative chromosome painting in other Brassicaceae species.

Lysak M ，Fransz P ，Schubert I 《-》

Distribution of the tandem repeat sequences and karyotyping in cucumber (Cucumis sativus L.) by fluorescence in situ hybridization.

We analyzed repeat sequences composition in the genome of cucumber inbred line 9930 using whole-genome shotgun reads. The analysis showed that satellite DNA sequences are the most dominant components in the cucumber genome. The distribution pattern of several tandem repeat sequences (Type I/II, Type III and Type IV) on cucumber chromosomes was visualized using fluorescence in situ hybridization (FISH). The FISH signals of the Type III and 45S rDNA provide useful cytogenetic markers, whose position and fluorescence intensity allow for easy identification of all somatic metaphase chromosomes. A karyotype showing the position and fluorescence intensity of several tandem repeat sequences is constructed. The establishment of this FISH-based karyotype has created the basis for the integration of molecular, genetic and cytogenetic maps in Cucumis sativus and for the ultimate genome sequencing project as well.

Han YH ，Zhang ZH ，Liu JH ，Lu JY ，Huang SW ，Jin WW ... -  《-》

Nuclear architecture and chromosome dynamics in the search of the pairing partner in meiosis in plants.

The formation of haploid gametes in organisms with sexual reproduction requires regular bivalent chromosome pairing in meiosis. In many species, homologous chromosomes occupy separate territories at the onset of meiosis. To be paired at metaphase I, they need to be brought into a close proximity for interactions that include homology recognition and the establishment of some form of bonds. How homologues find each other is one of the least understood meiotic events. Plant species with large or medium sized genomes, such as wheat or maize, are excellent materials for the cytological analysis of chromosome dynamics at early meiosis, but genes that control meiosis have been identified mainly in small genome species such as Arabidopsis thaliana. This review is focused on the contribution studies on plants are providing to the knowledge of the initial steps of the meiotic process.

Naranjo T ，Corredor E 《-》