- #1
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Why is the DNA in eukaryotes an open ended string rather than a closed loop?
DNA in Eukaryotes: Open Ended Strings vs Closed Loops
- Thread starter arildno
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SUMMARY
The discussion centers on the structural differences between eukaryotic linear DNA and prokaryotic circular DNA. Participants argue that eukaryotic DNA's open-ended string form facilitates the development of complex organisms and enhances genetic recombination during sexual reproduction. The conversation highlights that linear chromosomes may have evolved to stabilize genetic material, while circular chromosomes are more common in bacteria due to their evolutionary advantages. The role of gene mixing through meiosis is emphasized as a significant factor favoring linear DNA in eukaryotes.
PREREQUISITES- Understanding of eukaryotic and prokaryotic cell structures
- Knowledge of DNA structure and function
- Familiarity with genetic recombination and meiosis
- Basic concepts of evolutionary biology
- Research the evolutionary advantages of linear DNA in eukaryotes
- Explore the mechanisms of genetic recombination in meiosis
- Investigate the stability of linear versus circular DNA
- Read about artificial circular chromosome construction in yeast
Biologists, geneticists, and evolutionary scientists interested in the structural and functional differences between eukaryotic and prokaryotic DNA, as well as those studying genetic recombination and evolutionary biology.
- #2
spuriousmonkey
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because it is too long to be in a loop?
- #3
Monique
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..something with D-branes.. I don't remember 
But seriously, it is a good question.. let's turn it around: why is the DNA in prokaryotes circular and when did the separation between circular and linear DNA start. I guess spuriousmonkey has a point.
But seriously, it is a good question.. let's turn it around: why is the DNA in prokaryotes circular and when did the separation between circular and linear DNA start. I guess spuriousmonkey has a point.
- #4
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This is how I think about it:
that by using an open ended string form, it is easier to build up
a more complex organism which might carve out new ecological niches for themselves.
But since this is wild, unsubstantiated speculation from my side, I wanted to hear an expert's view on the matter..
that by using an open ended string form, it is easier to build up
a more complex organism which might carve out new ecological niches for themselves.
But since this is wild, unsubstantiated speculation from my side, I wanted to hear an expert's view on the matter..
- #5
iansmith
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I don't think it is a question of length. Many bacteria have more than one chromosome and if you add all the genetic material (including plasmid) some bacteria have large genome. Linear chromsome tend to be unstable if some component are not present. Circular chromosome can be done artificially in yeast (http://www.nature.com/cgi-taf/DynaPage.taf?file=/ng/journal/v20/n2/abs/ng1098_203.html)
I think the difference between linear and circular is probably due to their distinct evolution and early in their evolution, eukaryotes acquire genes that stabilize the linear form. As far as complexity and exploting unique niche, bacteria are ahead of eukaryotes. Linear chromsome seems better suite for sexual reproduction. Recombination between two linear chromosome seem to be easier than circular DNA.
This is paper on the evolution of linear chromosome in bacteria.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T2W-405SX5F-1&_user=458507&_handle=B-WA-A-A-BW-MsSAYZW-UUA-AUYZAZDVBE-AUYBDVYWBE-BEBWEBBUY-BW-U&_fmt=summary&_coverDate=05%2F05%2F2000&_rdoc=1&_orig=browse&_srch=%23toc%234929%232000%23998139997%23192052!&_cdi=4929&view=c&_acct=C000022002&_version=1&_urlVersion=0&_userid=458507&md5=66cbcaff630244073273ac3dca1eed2f
I think the difference between linear and circular is probably due to their distinct evolution and early in their evolution, eukaryotes acquire genes that stabilize the linear form. As far as complexity and exploting unique niche, bacteria are ahead of eukaryotes. Linear chromsome seems better suite for sexual reproduction. Recombination between two linear chromosome seem to be easier than circular DNA.
This is paper on the evolution of linear chromosome in bacteria.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T2W-405SX5F-1&_user=458507&_handle=B-WA-A-A-BW-MsSAYZW-UUA-AUYZAZDVBE-AUYBDVYWBE-BEBWEBBUY-BW-U&_fmt=summary&_coverDate=05%2F05%2F2000&_rdoc=1&_orig=browse&_srch=%23toc%234929%232000%23998139997%23192052!&_cdi=4929&view=c&_acct=C000022002&_version=1&_urlVersion=0&_userid=458507&md5=66cbcaff630244073273ac3dca1eed2f
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- #6
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iansmith, great!
So, linear DNA is the best tool for gene-mixing when gene-mixing is to occur by means of sexual reproduction?
So, linear DNA is the best tool for gene-mixing when gene-mixing is to occur by means of sexual reproduction?
- #7
Monique
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I think he has a very good point too.. on average 40 cross-overs occur during meiosis, I don't see that happening with circular DNA.. :)
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