Which regions of the genome are best suited for generating DNA Barcodes for species identification?
Which regions of the genome are best suited for generating DNA Barcodes for species identification?
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Correct Answer: Option B
Explanation
DNA barcoding: organellar genes are best suited:DNA barcoding uses a standardised short DNA sequence from the genome to identify species:Ideal barcode properties:• Universal primers for PCR amplification across a wide range of species• Conserved enough for primer annealing• Variable enough to distinguish closely related speciesStandard DNA barcodes:• Animals: COI (Cytochrome c Oxidase I, mitochondrial gene) — evolves at ~2% per million years• Plants: rbcL + matK (both chloroplast genes); ITS (nuclear ribosomal ITS) for fungi• Fungi: ITS (Internal Transcribed Spacer, ribosomal RNA gene region)Organellar genes (mitochondrial + chloroplast) are best because:• Many copies per cell → easy PCR amplification• Maternal inheritance → well-defined phylogenetic signal• Known evolution rates suitable for species-level resolutionWhy not histones or non-coding regions: histones evolve too slowly; non-coding regions too variable with no universal primers.Answer: Organellar genes (COI, rbcL, matK) are best for DNA barcoding due to universal primers and appropriate variability.