Chapter 13, Problem 1CHI

Streptomyces coelicolor has a linear chromosome. Interestingly, there are no genes that encode essential proteins near the ends of the chromosome in this bacterium. Why do you think this is the case?

Summary Introduction

Streptomyces coelicolor is characterized by a soil-dwelling Gram-positive, filamentous bacterium, which belongs to Streptomyces genus. It is well known for their capability to generate complex secondary metabolites such as antibiotics. It is considered as the best studied Streptomyces strain. Therefore, it becomes a model organism for all Streptomyces species.

Explanation of Solution

Most eukaryotic organisms possess linear chromosomes and their end portions are termed as telomeres. Telomeres comprised of repetitive DNA molecules and lacks genes. During the replication of DNA, since the ends of the linear chromosomes are fragile, some of the DNA telomere is lost. As a result, it is difficult to replicate the DNA ends accurately.

Similarly, the Streptomyces bacteria have linear plasmids and linear chromosomes with terminal inverted repeats. Therefore, the above explained situation is seen in the Streptomyces species.