Evidence that mitochondria and plastids arose from bacteria is as follows
- New mitochondria and plastids are formed only through a process similar to binary fission.
- If a cell's mitochondria or chloroplasts are removed, the cell does not have the means to create new noes. For example, in some algae, such as Euglena, th plastids can be destroyed by certain chemicals or prolonged absence of light without otherwise affecting the cell. In such a case, the plastids will not regenerate.
- transport proteins called porins are found in the outer membranes of mitochondria and chloroplasts, are also found in bacterial cell membranes.
- a membrane lipid cardiolipin is exclusively found in the inner mitochondrial membrane and bacterial membrane.
- both mitochondria and plastids contain single circular DNA that is different from that is similar to that of bacteria ( both in their size and structure).
- genome comparisons indicate that cyanobacteria contributed to the genetic origin of plastids.
- DNA sequence analysis and phylogenetic estimates suggest that nuclear DNA contains genes that probably came from plastids.
- these organelles' ribosomes are like those found in bacteria (70S).
- proteins of organelle origins, like those of bacteria, use N-formylmethionine as the initiating amino acid.
- mitochondria have several enzymes and transport systems similar to those of bacteria.