For DNA-based microbial community surveys, why is metagenomic sequencing superior to culture-dependent methods when estimating true diversity?
- AIt retrieves functional genes from uncultured taxa
- BIt eliminates the need for bioinformatic analysis
- CIt guarantees longer read lengths
- DIt avoids PCR amplification errors
Show answer and explanation
Correct answer: (a) It retrieves functional genes from uncultured taxa
Explanation
Most micro-organisms in nature, by some estimates more than 99%, cannot be grown in the laboratory. Culture-dependent methods therefore see only the few species that grow easily on lab media, and miss the rest.
Metagenomic sequencing extracts and sequences all the DNA directly from a sample (such as soil or water). So it finds the genes, including their functions, of organisms that have never been cultured, and gives a much truer picture of diversity.
It still needs a great deal of bioinformatics, and it does not by itself guarantee longer reads or freedom from all errors.