A consensus genetic map of sorghum that integrates multiple component maps and high-throughput Diversity Array...

Area of Science:

• Genomics
• Plant Genetics
• Molecular Biology

Background:

• Sorghum genome mapping has evolved from RFLP to AFLP, SSR, and DArT markers.
• Integrating diverse genetic linkage data, especially from DArT, with existing maps is crucial for sorghum genomics.
• Previous efforts resulted in multiple independent sorghum genetic linkage maps.

Purpose of the Study:

• To create a high-density sorghum consensus genetic map by integrating six independent component maps.
• To assess the colinearity and consistency of marker order across different sorghum mapping datasets.
• To establish a unified reference map incorporating SSR, AFLP, and DArT markers for improved sorghum genome analysis.

Main Methods:

• Construction of six individual sorghum component maps using MultiPoint software.
• Development of a framework consensus map using a "Neighbours" approach with integrated bridge markers.
• Projection of remaining markers onto the framework map to create a comprehensive integrated map.

Main Results:

• A sorghum consensus map was generated with 1997 markers across 10 chromosomes, spanning 1603.5 cM at a density of 1 marker/0.79 cM.
• The consensus map includes 1190 DArT loci and 839 other loci (SSRs, AFLPs), with DArT markers comprising 58.6% of the markers on average per chromosome.
• High consistency in marker order was observed across the six component maps, with good agreement in inter-marker distances.

Conclusions:

• The consensus map provides a more complete sorghum genome coverage and fills gaps present in individual maps.
• It serves as a valuable reference resource for genetic studies across different sorghum genetic backgrounds.
• Facilitates the transfer of genetic information between marker technologies and integrates DArT markers with other genomic resources for molecular breeding programs.