Objectives:

Understanding the DNA sequence searching algorithm and difference from the sequence similarity calculation.

Please do the followings:

1. Select randomly five 16S sequences from this data set.
2. Search them against NCBI NR/NT database at https://blast.ncbi.nlm.nih.gov/Blast.cgi.
3. Search them using EzBioCloud “Identify” at https://www.ezbiocloud.net/identify.

Please answer the following questions:

1. Summarize the results of two searches.
2. Are the top hits are the same? If not, why?
3. What are the meanings of scores/indexes given by BLAST and EzBioCloud searches?
4. Is there similarity/identity measure in two searches? Are they the same or not? Can they be used for the taxonomic purposes?

By Jon Jongsik Chun