Genetic System of Chloroplasts

Chloroplasts are ubiquitous organelles in green plants and are the sole repositories of photosynthesis. As the abnormalities in phenotype color in plants, such as striped, variegated, pale green, albino, etc., are easily observable, hereditary determinants of green-color characters have been studied in genetics from its beginning, and soon it was found that these abnor-malities are often inherited maternally through cyto-plasm in a non-Mendelian fashion. Later, it was con-firmed that chloroplasts have their own unique DNA. Then, in addition to mutations inherited through the cytoplasm, many cases of Mendelian inheritance due to the mutations in nuclear determinants of the similar green-color characters were also observed. At present it is well established that chloroplasts are