HIGH-RESOLUTION CYTOGENETIC MAPPING OF MEIOTIC RECOMBINATION HOTSPOTS IN CROP SPECIES

Abstract

Background: Meiotic recombination is a key biological process for generating genetic diversity and controlling chromosome segregation during meiosis. Recombination hotspots are important for understanding genome organization and improving crop breeding strategies.

Objective: The goal of this study was to investigate the distribution and cytogenetic characteristics of meiotic recombination hotspots in major crop species by employing high-resolution chromosome mapping techniques.
Methodology: Chromosomal analyses were carried out in wheat, rice and maize using fluorescence in situ hybridization (FISH), immunolocalization of recombination proteins and high-density SNP marker mapping. Recombination frequencies, crossover localization patterns and hotspot densities were studied for different chromosomal regions. To improve the accuracy of hotspot detection, we combined cytological imaging with molecular marker-assisted analyses.

Findings: It identified 185 recombination hotspots in wheat, 152 in rice and 171 in maize. Higher crossover rates were concentrated in subtelomeric regions and gene dense euchromatic regions. Maize (0.22) showed the highest mean crossover frequency, indicating a high recombination activity in comparison with wheat (0.18) and rice (0.14).
Conclusion: High resolution cytogenetic mapping is a powerful tool to detect recombination hotspot regions relevant for crop genome organization and evolutionary diversity. These results validate the applicability of recombination hotspot analysis for marker-assisted breeding and precision crop improvement programs.