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Modern hexaploid wheat (Triticum aestivum L.; AABBDD) has evolved from a hybrid of tetraploid wheat (closely related to Triticum turgidum L. ssp. durum (Desf.) Husn., AABB) and goatgrass (Aegilops tauschii Coss., DD). Variations in chromosome structure and ploidy have played important roles in wheat evolution. How these variations occur and their role in expanding the genetic diversity of modern wheat remain largely unknown. Synthetic hexaploid wheat (SHW) can be used to investigate chromosome variations that occur during the early generations of existence. SHW lines derived by crossing durum wheat 'Langdon' with 12 Ae. tauschii accessions were analyzed using oligonucleotide probe multiplex fluorescence in situ hybridization (FISH) of metaphase chromosomes and SNP markers. Cluster analysis based on SNP markers categorizes them into three groups. Among 702 plants from the [S.sub.8] and [S.sub.9] generations, 415 (59.12%) carried chromosome variations involving all 21 chromosomes, but with different frequencies for each chromosome and sub-genome. Total chromosome variation frequencies varied between lines, but there was no significant difference among the three groups. The non-random chromosome variations in the SHW lines detected in this study may indicate that similar variations occurred in the early stages of wheat polyploidization and played important roles in wheat evolution. Key words: Triticum aestivum, Triticum turgidum, Aegilops tauschii, chromosome evolution, oligonucleotide probe multiplex FISH. Le ble hexaplo'ide moderne (Triticum aestivum L.; AABBDD) a evolue a partir d'un hybride entre un ble tetraplo'ide (tres apparente au Triticum turgidum L. ssp. durum (Desf.) Husn., AABB) et l'egilope de Tausch (Aegilops tauschii Coss., DD). Les variations dans la structure des chromosomes et la plo'idie ont joue des roles importants dans revolution du ble. Comment ces variations sont survenues et leur role dans l'expansion de la diversite genetique chez les bles modernes demeure largement inconnu. Des bles hexaplo'ides synthetiques (SHW) peuvent servir a etudier la variation chromosomique qui survient dans les premieres generations suivant leur synthese. Des lignees SHW derivees de croisements entre le ble dur 'Langdon' et douze accessions de l'Ae. tauschii ont ete analysees au moyen de marqueurs SNP et d'hybridations in situ en fluorescence (FISH) realisees en employant un multiplexe de sondes oligonucleotidiques sur des chromosomes en metaphase. Des analyses de groupement fondees sur les marqueurs SNP ont permis de categoriser en trois groupes. Parmi les702plantesissuesdesgenerations[S.sub.8] et [S.sub.9], 415 (59,12 %) presentaient une variation chromosomique et les 21 chromosomes etaient concernes par cette variation, mais les frequences pour chaque chromosome et sousgenome etaient variables. Les frequences totales en matiere de variation chromosomique differaient selon les lignees, mais aucune difference significative entre les trois groupes n'a ete trouvee. Les variations chromosomiques non-aleatoires chez les lignees SHW detectees dans ce travail indiquent possiblement qu'une variation semblable est survenue dans les premiers stades de la polyploidisation chez le ble et aurait joue des roles importants dans revolution du ble. [Traduit par la Redaction] Mots-cles : Triticum aestivum, Triticum turgidum, Aegilops tauschii, evolution des chromosomes, FISH employant un multiplexe de sondes oligonucleotidiques., Introduction Polyploidization is a frequent evolutionary event in many eukaryotes (Soltis and Kliebenstein 2015; Van de Peer et al. 2017) that facilitates genome evolution through rapid genetic and epigenetic changes [...]

For peanut, the lack of stable cytological markers is a barrier to tracking specific chromosomes, elucidating the genetic relationships between genomes and identifying chromosomal variations. Chromosome mapping using single-copy oligonucleotide (oligo) probe libraries has unique advantages for identifying homologous chromosomes and chromosomal rearrangements. In this study, we developed two whole-chromosome single-copy oligo probe libraries, LS-7A and LS-8A, based on the reference genome sequences of chromosomes 7A and 8A of Arachis duranensis. Fluorescence in situ hybridization (FISH) analysis confirmed that the libraries could specifically paint chromosomes 7 and 8. In addition, sequential FISH and electronic localization of LS-7A and LS-8A in A. duranensis (AA) and A. ipaensis (BB) showed that chromosomes 7A and 8A contained translocations and inversions relative to chromosomes 7B and 8B. Analysis of the chromosomes of wild Arachis species using LS-8A confirmed that this library could accurately and effectively identify A genome species. Finally, LS-7A and LS-8A were used to paint the chromosomes of interspecific hybrids and their progenies, which verified the authenticity of the interspecific hybrids and identified a disomic addition line. This study provides a model for developing specific oligo probes to identify the structural variations of other chromosomes in Arachis and demonstrates the practical utility of LS-7A and LS-8A. [ABSTRACT FROM AUTHOR]

Abstract: Single-strand oligonucleotides (SSONs hereafter) as probes are becoming a powerful method of chromosome painting in many species. In this study, nine SSONs ([(ACT).sub.10], [(ACT).sub.19], Knob-1, Knob-2, Knob-3, CentC69-1, MR68-3, [...]

Abstract: In comparison with general FISH for preparing probes in terms of time and cost, synthesized oligonucleotide (oligo hereafter) probes for FISH have many advantages such as ease of design, [...]