Q.64 Molecular techniques used for the identification of micro-organisms from environmental samples includes

1. Metagenomics
2. CARD-FISH
3. Denaturing gradient gel electrophoresis
4. ELISA
5. Phylochips

Choose the correct answer from the options given below :

1. A, C, D only
2. A, D, E only
3. A, C, E only
4. A, B, C only

   A, C, E only is the correct answer for molecular techniques identifying microorganisms from environmental samples. Metagenomics, DGGE, and phylochips directly analyze microbial DNA/RNA communities without cultivation, while CARD-FISH and ELISA do not qualify as primary molecular methods for this purpose.​

   Technique Classification

   Environmental microbiology relies on culture-independent molecular methods to profile unculturable microbes. These target nucleic acids or phylogenetic markers from bulk samples like soil or water.​

   Method Breakdown

   • Metagenomics (A): Sequences total DNA from samples, identifying microbes via 16S rRNA or whole genomes.​

   • CARD-FISH (B): Fluorescence in situ hybridization variant using catalyzed reporter deposition; visualizes cells but antibody/probe-based, not bulk molecular profiling.​

   • DGGE (C): Denaturing gradient gel electrophoresis separates PCR-amplified 16S rRNA fragments by sequence differences, revealing community diversity.​

   • ELISA (D): Immunoassay detecting specific proteins/antigens; serological, not molecular (no nucleic acid analysis).​

   • Phylochips (E): Microarrays hybridizing environmental DNA to taxon-specific probes for phylogenetic identification.​

   Option Analysis

   Option	Techniques	Why Valid/Invalid	Correct?
   A, C, D only	Metagenomics, DGGE, ELISA	Excludes phylochips; ELISA not molecular.	No ​
   A, D, E only	Metagenomics, ELISA, Phylochips	ELISA immunological, not molecular.	No ​
   A, C, E only	Metagenomics, DGGE, Phylochips	All nucleic acid-based for community profiling.	Yes
   A, B, C only	Metagenomics, CARD-FISH, DGGE	CARD-FISH probe/visual despite molecular probes.	No ​

   Molecular techniques identification microorganisms environmental samples like metagenomics DGGE phylochips enable culture-free profiling, essential for GATE Life Sciences environmental microbiology preparation.

   Valid Methods

   Metagenomics shotgun sequences communities; DGGE fingerprints diversity; phylochips detect taxa via hybridization.​

   Invalid Methods

   ELISA protein-based immunoassay; CARD-FISH cellular imaging despite probes.​

   GATE Strategy

   Select A, C, E—focus on DNA/RNA profiling techniques.​