Plastid DNA

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Chloroplast DNA Interactive gene map of chloroplast DNA from Nicotiana tabacum. Segments with labels on the inside reside on the B strand of DNA, segments with labels on the outside are on the A strand. Notches indicate introns.

Plastid DNA (ptDNA), also known as chloroplast DNA (cpDNA or ctDNA) in photosynthetic organisms, is the DNA located in chloroplasts, which are photosynthetic organelles located within the cells of some eukaryotic organisms, as well as some reduced plastids, such as apicoplasts. Chloroplasts, like other types of plastid, contain a genome separate from that in the cell nucleus. The existence of chloroplast DNA was identified biochemically in 1959, and confirmed by electron microscopy in 1962. The discoveries that the chloroplast contains ribosomes and performs protein synthesis revealed that the chloroplast is genetically semi-autonomous. The first complete chloroplast genome sequences were published in 1986, Nicotiana tabacum (tobacco) by Sugiura and colleagues and Marchantia polymorpha (liverwort) by Ozeki et al. Since then, tens of thousands of chloroplast genomes from various species have been sequenced.