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DNA profiling (also called DNA fingerprinting and genetic fingerprinting) is the process of determining an individual's deoxyribonucleic acid characteristics. DNA analysis intended to identify a species, rather than an individual, is called DNA barcoding .
In eukaryotic cells (cells that package their DNA within a nucleus), chromosomes consist of very long linear double-stranded DNA molecules. During the S-phase of each cell cycle ( Figure 1 ), all of the DNA in a cell is duplicated in order to provide one copy to each of the daughter cells after the next cell division.
1869: Friedrich Miescher discovers a weak acid in the nuclei of white blood cells that today we call DNA. In 1871 he isolated cell nuclei, separated the nucleic cells from bandages and then treated them with pepsin (an enzyme which breaks down proteins).
Eukaryogenesis, the process which created the eukaryotic cell and lineage, is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The process is widely agreed to have involved symbiogenesis , in which an archeon and a bacterium came together to create the first eukaryotic ...
Eukaryotic cells, containing membrane-bound organelles with diverse functions, probably derived from prokaryotes engulfing each other via phagocytosis. (See Symbiogenesis and Endosymbiont). Bacterial viruses (bacteriophages) emerge before or soon after the divergence of the prokaryotic and eukaryotic lineages. [44]
The eukaryotic cell seems to have evolved from a symbiotic community of prokaryotic cells. DNA-bearing organelles like mitochondria and chloroplasts are remnants of ancient symbiotic oxygen-breathing bacteria and cyanobacteria, respectively, where at least part of the rest of the cell may have been derived from an ancestral archaean prokaryote ...
Starting in the mid-1950s, Arthur Kornberg began to study the mechanism of DNA replication. [4] By 1957 he has identified the first DNA polymerase. [5] The enzyme was limited, creating DNA in just one direction and requiring an existing primer to initiate copying of the template strand.
The large genome sizes of eukaryotic cells, which range from 12 Mbp in S. cerevisiae to more than 100 Gbp in some plants, necessitates that DNA replication starts at several hundred (in budding yeast) to tens of thousands (in humans) origins to complete DNA replication of all chromosomes during each cell cycle.