Palindromic sequence impedes sequencing-by-ligation mechanism.

Area of Science:

• Genomics
• Molecular Biology
• Biotechnology

Background:

• Next-generation sequencing (NGS) utilizes either by synthesis or by ligation mechanisms.
• Existing NGS platforms like 454 and Solexa use by synthesis, while SOLiD uses by ligation.
• The impact of palindromic sequences on sequencing efficacy remains underexplored.

Purpose of the Study:

• To investigate the effect of palindromic sequences on sequencing efficacy across different NGS platforms.
• To compare the performance of sequencing-by-ligation and sequencing-by-synthesis in handling palindromic DNA regions.

Main Methods:

• Clonally amplified a paired-end ditag sequence with a 24-bp palindromic region from E. coli.
• Generated a sequencing library using MmeI-digested fragments for the SOLiD 5500xl sequencer.
• Compared sequencing results with traditional sequencing-by-synthesis platforms.

Main Results:

• Sequencing-by-synthesis platforms (e.g., ABI) successfully read through the palindromic region.
• SOLiD 5500xl (sequencing-by-ligation) failed to read the palindromic region, producing random sequences.
• Readable tag sequences near the palindromic region became obscured on the SOLiD platform.

Conclusions:

• SOLiD machines employing sequencing-by-ligation are incapable of accurately sequencing through palindromic regions.
• Sequencing-by-synthesis sequencers demonstrate no difficulty in reading palindromic sequences.
• Palindromic sequences pose a significant obstacle for sequencing-by-ligation platforms.