You have sequenced the genome of the bacterium Salmonella ty

You have sequenced the genome of the bacterium Salmonella typhimurium and find a protein that is 100% identical to a protein in the bacterium Escherichia coli. When you compare the sequences of the S. typhimurium and E. coli genes, however, you find that their DNA sequences are only 87% identical Explain this observation-how could identical proteins be encoded by different DNA?

Solution

1. Gene cluster:

A gene cluster is part of a gene family. A gene cluster is a group of two or more genes found within an organism\'s DNA that encode for similar polypeptides, or proteins, which collectively share a generalized function and are often located within a few thousand base pairs of each other. The size of gene clusters can vary significantly, from a few genes to several hundred genes.Portions of the DNA sequence of each gene within a gene cluster are found to be identical; however, the resulting protein of each gene is distinctive from the resulting protein of another gene within the cluster.