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Mitochondrial DNA is a main source of this extrachromosomal DNA in eukaryotes. [5] The fact that this organelle contains its own DNA supports the hypothesis that mitochondria originated as bacterial cells engulfed by ancestral eukaryotic cells. [6] Extrachromosomal DNA is often used in research into replication because it is easy to identify ...
The mosaic marker is a gene which exhibits a visible phenotype change between the functioning and non-functioning alleles. For example, ncl-1, located in chromosomal DNA, exhibits a larger nucleolus than the wild-type allele, which is in the array. Thus, cells which exhibit larger nucleoli have usually not retained the extrachromosomal array.
Extrachromosomal circular DNA (eccDNA) is a type of double-stranded circular DNA structure that was first discovered in 1964 by Alix Bassel and Yasuo Hotta. [1] In contrast to previously identified circular DNA structures (e.g., bacterial plasmids, mitochondrial DNA, circular bacterial chromosomes, or chloroplast DNA), eccDNA are circular DNA found in the eukaryotic nuclei of plant and animal ...
Circular extrachromosomal DNA are not only found in yeast but other eukaryotic organisms. [15] [16] A regulated formation of eccDNA in preblastua Xenopus embryos has been developed. The population of circular rDNA is decreased in embryos, indicative of the circular rDNA migrating to linear DNA, as was shown in their analysis on 2D gel ...
Double minutes (DMs) are small fragments of extrachromosomal DNA, which have been observed in a large number of human tumors including breast, lung, ovary, colon, and most notably, neuroblastoma. They are a manifestation of gene amplification as a result of chromothripsis , [ 1 ] during the development of tumors, which give the cells selective ...
The term plasmid was coined in 1952 by the American molecular biologist Joshua Lederberg to refer to "any extrachromosomal hereditary determinant." [11] [12] The term's early usage included any bacterial genetic material that exists extrachromosomally for at least part of its replication cycle, but because that description includes bacterial viruses, the notion of plasmid was refined over time ...
Gene mapping or genome mapping describes the methods used to identify the location of a gene on a chromosome and the distances between genes. [2] [3] Gene mapping can also describe the distances between different sites within a gene. The essence of all genome mapping is to place a collection of molecular markers onto their respective positions ...
The crystal structure of the Ter DNA-Tus protein complex (A) showing the nonblocking and the fork-blocking faces of Tus. (B) A cross-sectional view of the helicase-arresting surface. Replication of the DNA separating the opposing replication forks leaves the completed chromosomes joined as ‘catenanes’ or topologically interlinked circles ...