What are 3 pieces of evidence to support the theory of endosymbiosis?

A good example of endosymbiosis is the mitochondria. Three pieces of evidence that suggest the mitochondria was not an original organelle in cells are:

1. They have their own membranes

2. They reproduce by pinching in half which is very similar if not the same to binary fission of bacteria

3. They have their own genomes which are passed off to the offspring.