During analysis of Next-Gen Sequencing data, what is the advantage of BAM files over SAM files?
During analysis of Next-Gen Sequencing data, what is the advantage of BAM files over SAM files?
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Correct Answer: Option C
Explanation
BAM files vs. SAM files in NGS data analysis:SAM (Sequence Alignment/Map) vs BAM (Binary Alignment/Map):• SAM: plain TEXT format; human-readable; each line = one read alignment.• BAM: BINARY-compressed version of SAM; NOT human-readable.Key differences:• File size: BAM files are approximately 3–5 times SMALLER than equivalent SAM files.• Processing speed: BAM files are faster to read/write computationally.• Information content: IDENTICAL — BAM encodes exactly the same information as SAM, just in compressed binary format.• Indexing: BAM files can be indexed (.bai file) for rapid random access to specific genomic regions; SAM cannot be indexed this way.Tools: samtools, Picard, GATK all work natively with BAM; conversion: samtools view -b.BGZF compression: BAM uses blocked gzip format (BGZF) allowing random access while compressed.Answer: BAM files are binary-compressed SAM files; they are SMALLER (faster to transfer/store) but contain the same information.