Application of inter simple sequence repeat (ISSR) markers to plant genetics

Area of Science:

• Genomics
• Molecular Biology
• Plant Science

Background:

• Microsatellites, or Simple Sequence Repeats (SSRs), are common in eukaryotic genomes.
• Developing SSR markers typically requires known flanking sequences for PCR primer design, posing a significant bottleneck.
• Inter Simple Sequence Repeat (ISSR) fingerprinting was developed to bypass the need for sequence knowledge.

Purpose of the Study:

• To introduce and demonstrate the utility of Inter Simple Sequence Repeat (ISSR) fingerprinting.
• To evaluate ISSR fingerprinting for genetic analysis in sorghum and banana.
• To compare the level of polymorphism detected by ISSR with other methods like RFLP and RAPD.

Main Methods:

• ISSR utilizes primers based on repeat sequences with degenerate 3'-anchors.
• The method amplifies sequences between SSRs, creating a multilocus marker system.
• PCR products are radiolabeled and visualized on polyacrylamide gels.

Main Results:

• ISSR fingerprinting successfully generated 20-100 bands per lane in tested plant species.
• ISSR analysis typically reveals higher polymorphism levels compared to RFLP and RAPD.
• The enhanced polymorphism detection in ISSR is linked to technical aspects of the detection methodology.

Conclusions:

• ISSR fingerprinting is a valuable tool for genetic fingerprinting, diversity analysis, and genome mapping without requiring prior sequence information.
• The higher polymorphism observed with ISSR is primarily a technical artifact of the detection method, not necessarily greater genetic diversity.
• ISSR provides an efficient alternative for genetic studies, particularly when sequence data is limited.