The possible presence of organelle DNA inside the nuclear genome was suggested after finding of homologous structure to the mitochondrial DNA, which was shortly after the discovery of the presence of an independent DNA within the organelles in 1967. This topic stayed untouched until the 1980s. Initial evidence that DNA could move among cell compartments came when fragments of chloroplast DNA were found in the maize mitochondrial genome with the help of cross-hybridization, between chloroplast and mitochondrial DNA, and physical mapping of homologous regions. After this initial observation, Ellis coined the name "promiscuous DNA" in order to signify the transfer of DNA intracellularly from one organelle to the other and is the presence of organelle DNA in multiple cellular compartments. This is not only an important discovery on its own, but is also highly informative and helpful for understanding the evolutionary process and the time period different occurrence might take place. The searching for mtDNA in nuclear DNA continued until 1994 when the recent remarkable transposition of 7.9 kb of a typically 17.0-kb mitochondrial genome to a specific nuclear chromosomal position in the domestic cat was reported. This is the time that NUMT was coined to designate the large stretches of mitochondrial DNA in the genome.