This photograph is inconsistent with a eukaryotic chromosome that contains only simple, linear DNA

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UV photomicrograph of remnants of mouse L1210 cells stained with acridine orange (400x  magnification)

This remarkable photograph was taken at an Ohio State University laboratory over 20 years ago. To date, I have found nothing in the literature that matches it, much less any sort of explanation for what these circles might be. If anyone has come across something like this in the literature or in their laboratory, please e mail me at frank@eukaryotes.info.

Anyone who has ever taken a general biology course that describes DNA knows that viral and bacterial DNA is predominantly circular in nature. What is lesser known is that circular DNA can also be found within the eukaryotic genome, usually associated with DNA rearrangements during differentiation. Are these eukaryotic circular elements merely obscure curiosities; exceptions to the rule, or could they be something more?  The prevailing dogma suggests that the genes within eukaryotic DNA are linearly arrayed, based on data originally acquired from  chromosomal recombination and later “validated” by chromosomal sequencing data which involves “jumping over” and editing out sections of the DNA not amenable to sequencing protocols, i.e., DNA that is not linear in nature. When these troublesome sequences are removed from the equation, the bioinformatician can now splice together the remaining DNA into a product more to their liking: simple linear DNA. Yet problems remain. How can enhancer elements increase transcription when they may be thousands of base pairs away from the promoter? Currently, the prevailing answer in the literature is to bring them together into a loop so they can interact. Could it be that the loop was there to begin with before the DNA was manhandled into linear conformity? If eukaryotic circular DNA is the exception, rather than the rule to eukaryotic chromosomal structure, how does one go about explaining the photomicrograph shown above?  DNA stains bright green when exposed to acridine orange.

I look forward to your comments. I can also be reached by e mail at frank@eukaryotes.info

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About frankabernathy

I am a retired cell biologist and alumnus of Ohio State University. I became interested in chromosomes as far back as the 1960's when I wrote a term paper on the effects of radiomimetic drugs on chromosomes. I was fascinated at how they could break apart and reform new structures so easily. I became further involved in the early 1970's after taking a cytogenetics course at the University of Arkansas. I took that knowledge with me to Ohio State in 1980 where I eventually worked on my research and completed my Ph.D. dissertation, "Studies on Eukaryotic DNA Superstructure". My studies and later research suggested that the DNA within the eukaryotic chromosome is not the simple, linear molecular thread so widely suggested in all the classic textbooks published today. Instead, it may be the culmination of a geologically rapid set of endosymbiotic events where microorganisms plug into each other to create something greater than themselves. Feel free to contact me at fabernathy@sbcglobal.net.
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