Download Full Text (1.0 MB)


Chromosomes are molecules of DNA that hold large quantities of genetic material in an organism. Generally, in nature, eukaryotic chromosomes are linear while prokaryotic chromosomes are circular. Since they are linear, eukaryotic chromosomes possess telomeres, or repetitive nucleotide sequences, on their ends. This significant difference in structure requires different additions to the basic replication process. In prokaryotes, replication starts at a single point on the chromosome and continues until the whole chromosome has been copied. In eukaryotes, replication happens in fragments with multiple starting points. Because of this more complicated replication process, the free 3’ ends of our DNA cannot be fully copied. Unchecked, this would lead to a progressive loss of important genetic information. To counteract this issue, most eukaryotic organisms express an enzyme telomerase to attach nucleotides onto the template telomere, which prevents wearing down of telomeres each time the cell gets copied. Despite the action of telomerase, we still lose telomere sequences as we age. If linear chromosomes create issues not found with circular chromosomes, this begs the question why did eukaryotic chromosomes evolve to be linear?

Publication Date



Arts and Humanities | Business | Education | Engineering | Higher Education | Life Sciences | Medicine and Health Sciences | Physical Sciences and Mathematics | Social and Behavioral Sciences

“The Never Ending Story:” Circularizing Ch. VIII in Saccharomyces cerevisiae



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.