103. Which of the following BLAST search program is used to find the putative function of a given
nucleotide sequence to search a protein sequence database?
1. BLASTX
2. BLASTP
3. BLASTN
4. BLASTZ

Correct Answer:

1. BLASTX

Explanation:

BLAST (Basic Local Alignment Search Tool) is a widely used tool for sequence comparison. Here’s how the different programs work:

1. BLASTX:
   BLASTX is used to search a protein sequence database with a nucleotide sequence (translated in all six reading frames). This is useful for finding the putative function of a given nucleotide sequence by comparing it to known protein sequences. The nucleotide sequence is translated into a protein sequence to search against protein databases.

2. BLASTP:
   BLASTP is used to compare a protein sequence to a protein sequence database. It does not work with nucleotide sequences.

3. BLASTN:
   BLASTN is used to compare a nucleotide sequence against a nucleotide sequence database. This is useful when you want to find similar nucleotide sequences, but it is not designed for searching protein databases.

4. BLASTZ:
   BLASTZ is a program used for multiple sequence alignment and is typically used to compare larger sequences, such as genomic sequences, rather than individual nucleotide or protein sequences.

Conclusion:

The BLASTX program is the most appropriate for finding the putative function of a nucleotide sequence by searching a protein sequence database.

Correct Answer: 1. BLASTX