Question

How would you answer the DSAP question shown below if there were no matches the BLASTN search of the nr/nt database and you only got the following matches in the second BLASTN search (i.e. no other matches besides those that are shown)?

1. The sequence is not in the nr/nt database.
2. The sequence is from a virus or other non-prokaryotic organism.
3. The sequence is from a prokaryotic organism that is not well-represented in the nr/nt database.
4. The sequence is from a prokaryotic organism that is closely related to duckweed Spirodela polyrhiza.

Answer 1

When a BLASTN search does not yield matches in the nr/nt database, there could be several possibilities.

Step-by-step explanation:

When the BLASTN search does not yield any matches in the nr/nt database, there could be several possibilities:

The sequence is not present in the nr/nt database.

The sequence is from a virus or another non-prokaryotic organism.

The sequence is from a prokaryotic organism that is not well-represented in the nr/nt database.

The sequence is from a prokaryotic organism closely related to duckweed Spirodela polyrhiza.

These possibilities indicate that the sequence either does not exist in the database or belongs to organisms that are not well-represented in the database.