Summative Questions for the Introduction to BLAST using human leptin

Author:Douglas L. Chalker
Last Update:Aug 31, 2019

Exercise Summary

In this exercise, you used the NCBI database to discover information about the leptin gene and its genetic link to obesity. You then downloaded the human leptin protein and used the BLAST bioinformatics tool to determine whether homologs of the human leptin gene are found in other organisms and used that information to consider how sequence similarity allows one to gain support for evolutionary relationships between species. You should now have a general understanding of how one can identify related DNA and protein sequences using tools that compare a specific sequence to a database of known sequences.

Summative Questions

Summary Question 1

List three types of information that one can access using NCBI databases

Summary Question 2

What is difference between percent identity and percent similarity in the output of a BLAST search?

Summary Question 3

In your own words, state how the output of a BLAST search can support the hypothesis that two organisms contain homologs of the same gene?