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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 .
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 ...
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 ...
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).
Its genetic material was most likely DNA, [15] so that it lived after the RNA world. [a] [18] The DNA was kept double-stranded by an enzyme, DNA polymerase, which recognises the structure and directionality of DNA. [19] The integrity of the DNA was maintained by a group of repair enzymes including DNA topoisomerase. [20]
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]
Using these x-rays and information already known about the chemistry of DNA, James D. Watson and Francis Crick demonstrated the molecular structure of DNA in 1953. [ 22 ] [ 23 ] Together, these discoveries established the central dogma of molecular biology , which states that proteins are translated from RNA which is transcribed by DNA.
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.