Mapping genes on an integrated sorghum genetic and physical map using cDNA selection technology.

Area of Science:

• Plant Genomics
• Molecular Biology
• Bioinformatics

Background:

• Sorghum is a vital cereal crop known for its environmental resilience and relatively small genome.
• Its genetic resources are valuable for comparative genomics with other grass species like rice and maize.
• Efficient gene discovery and mapping are crucial for understanding sorghum's genetic makeup.

Purpose of the Study:

• To develop and validate a modified cDNA selection protocol for sorghum gene discovery and mapping.
• To assess the efficiency and accuracy of the protocol for identifying gene sequence tags.
• To facilitate genome-wide gene discovery and comparative genomics in sorghum.

Main Methods:

• Modified cDNA selection protocol using arrayed BAC DNA.
• Hybridization of cDNA sequence tags to sorghum BACs.
• Sequencing and analysis of isolated cDNA tags and BACs.
• Mapping of identified genes and expressed sequence tags (ESTs).

Main Results:

• The protocol successfully isolated amplifiable cDNA sequence tags from sorghum BACs.
• Analysis of a sequenced BAC revealed detection of approximately 80% of known or predicted genes.
• Low occurrence of mislocated cDNA tags was observed.
• Two sorghum genes and 58 sorghum ESTs were mapped from 35 BACs, along with 31 cross-species homologous cDNA tags.

Conclusions:

• The modified cDNA selection procedure is effective for genome-wide gene discovery in sorghum.
• This method significantly aids in EST mapping and facilitates comparative genomics studies.
• The protocol enhances our ability to explore the sorghum genome and its relationship with other grasses.