Some species of the genus Aegilops, a wild relative of wheat, carry chromosomes that after introducing to wheat exhibit preferential transmission to progeny. Their selective retention is a result of the abortion of gametes lacking them due to induced chromosomal aberrations. These chromosomes are termed Gametocidal (Gc) and, based on their effects, they are categorized into three types: mild, intense or severe, and very strong. Gc elements within the same homoeologous chromosome groups of Aegilops (II, III, or IV) demonstrate similar Gc action. This review explores the intriguing dynamics of Gc chromosomes and encompasses comprehensive insights into their source species, behavioral aspects, mode of action, interactions, suppressions, and practical applications of the Gc system in wheat breeding. By delving into these areas, this work aims to contribute to the development of novel plant genetic resources for wheat breeding. The insights provided herein shed light on the utilization of Gc chromosomes to produce chromosomal rearrangements in wheat and its wild relatives, thereby facilitating the generation of chromosome deletions, translocations, and telosomic lines. The Gc approach has significantly advanced various aspects of wheat genetics, including the introgression of novel genes and alleles, molecular markers and gene mapping, and the exploration of homoeologous relationships within Triticeae species. The mystery lies in why gametes possessing Gc genes maintain their normality while those lacking Gc genes suffer abnormalities, highlighting an unresolved research gap necessitating deeper investigation.

• Klíčová slova
• Aegilops, Gc factors/elements/genes, Triticum, gametocidal, pollen-killer, segregation distorter, wheat,
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Bread wheat has a large and complex allohexaploid genome with low recombination level at chromosome centromeric and peri-centromeric regions. This significantly hampers ordering of markers, contigs of physical maps and sequence scaffolds and impedes obtaining of high-quality reference genome sequence. Here we report on the construction of high-density and high-resolution radiation hybrid (RH) map of chromosome 4A supported by high-density chromosome deletion map. A total of 119 endosperm-based RH lines of two RH panels and 15 chromosome deletion bin lines were genotyped with 90K iSelect single nucleotide polymorphism (SNP) array. A total of 2316 and 2695 markers were successfully mapped to the 4A RH and deletion maps, respectively. The chromosome deletion map was ordered in 19 bins and allowed precise identification of centromeric region and verification of the RH panel reliability. The 4A-specific RH map comprises 1080 mapping bins and spans 6550.9 cR with a resolution of 0.13 Mb/cR. Significantly higher mapping resolution in the centromeric region was observed as compared to recombination maps. Relatively even distribution of deletion frequency along the chromosome in the RH panel was observed and putative functional centromere was delimited within a region characterized by two SNP markers.

• Klíčová slova
• SNP iSelect array, Triticum aestivum, chromosome deletion bin map, endosperm radiation hybrid panel, radiation hybrid map, wheat chromosome 4A,
• Publikační typ
• časopisecké články MeSH

BACKGROUND: A complete genome sequence is an essential tool for the genetic improvement of wheat. Because the wheat genome is large, highly repetitive and complex due to its allohexaploid nature, the International Wheat Genome Sequencing Consortium (IWGSC) chose a strategy that involves constructing bacterial artificial chromosome (BAC)-based physical maps of individual chromosomes and performing BAC-by-BAC sequencing. Here, we report the construction of a physical map of chromosome 6B with the goal of revealing the structural features of the third largest chromosome in wheat. RESULTS: We assembled 689 informative BAC contigs (hereafter reffered to as contigs) representing 91% of the entire physical length of wheat chromosome 6B. The contigs were integrated into a radiation hybrid (RH) map of chromosome 6B, with one linkage group consisting of 448 loci with 653 markers. The order and direction of 480 contigs, corresponding to 87% of the total length of 6B, were determined. We also characterized the contigs that contained a part of the nucleolus organizer region or centromere based on their positions on the RH map and the assembled BAC clone sequences. Analysis of the virtual gene order along 6B using the information collected for the integrated map revealed the presence of several chromosomal rearrangements, indicating evolutionary events that occurred on chromosome 6B. CONCLUSIONS: We constructed a reliable physical map of chromosome 6B, enabling us to analyze its genomic structure and evolutionary progression. More importantly, the physical map should provide a high-quality and map-based reference sequence that will serve as a resource for wheat chromosome 6B.

• MeSH
• chromozomy rostlin MeSH
• fyzikální mapování chromozomů metody   MeSH
• genetické markery MeSH
• genová přestavba MeSH
• molekulární evoluce MeSH
• organizátor jadérka MeSH
• pořadí genů MeSH
• pšenice genetika   MeSH
• umělé bakteriální chromozomy genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• genetické markery MeSH