Quantitative high resolution mapping of HvMLH3 foci in barley pachytene nuclei reveals a strong distal bias and weak interference
| Autor: | Ruth M. Perry, James D. Higgins, Frank Wright, Candida Nibau, Luke Ramsay, Abdellah Barakate, Glyn Jenkins, Joanna Wnetrzak, Dylan Phillips |
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| Rok vydání: | 2013 |
| Předmět: |
0106 biological sciences
Genetic Linkage Physiology Molecular Sequence Data Arabidopsis interference chiasma Plant Science Biology Interference (genetic) 01 natural sciences Chromosomes Plant 03 medical and health sciences Genetic linkage Barley Chromosome regions Crossing Over Genetic In Situ Hybridization Fluorescence Phylogeny Hordeum vulgare 030304 developmental biology Genetics crossover 0303 health sciences Base Sequence Synaptonemal Complex Transverse filament Chromosome Mapping food and beverages Hordeum Chiasma Synaptonemal complex Genetic Loci MLH3 Pachytene Stage Sequence Alignment Genome Plant Recombination Research Paper 010606 plant biology & botany |
| Zdroj: | Journal of Experimental Botany |
| ISSN: | 1460-2431 0022-0957 |
| DOI: | 10.1093/jxb/ert079 |
| Popis: | In barley (Hordeum vulgare L.), chiasmata (the physical sites of genetic crossovers) are skewed towards the distal ends of chromosomes, effectively consigning a large proportion of genes to recombination coldspots. This has the effect of limiting potential genetic variability, and of reducing the efficiency of map-based cloning and breeding approaches for this crop. Shifting the sites of recombination to more proximal chromosome regions by forward and reverse genetic means may be profitable in terms of realizing the genetic potential of the species, but is predicated upon a better understanding of the mechanisms governing the sites of these events, and upon the ability to recognize real changes in recombination patterns. The barley MutL Homologue (HvMLH3), a marker for class I interfering crossovers, has been isolated and a specific antibody has been raised. Immunolocalization of HvMLH3 along with the synaptonemal complex transverse filament protein ZYP1, used in conjunction with fluorescence in situ hybridization (FISH) tagging of specific barley chromosomes, has enabled access to the physical recombination landscape of the barley cultivars Morex and Bowman. Consistent distal localization of HvMLH3 foci throughout the genome, and similar patterns of HvMLH3 foci within bivalents 2H and 3H have been observed. A difference in total numbers of HvMLH3 foci between these two cultivars has been quantified, which is interpreted as representing genotypic variation in class I crossover frequency. Discrepancies between the frequencies of HvMLH3 foci and crossover frequencies derived from linkage analysis point to the existence of at least two crossover pathways in barley. It is also shown that interference of HvMLH3 foci is relatively weak compared with other plant species. |
| Databáze: | OpenAIRE |
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