What is one piece of evidence for the endosymtic origin of eukaryotic organelles?

One compelling piece of evidence for the endosymbiotic origin of eukaryotic organelles, particularly mitochondria and chloroplasts, is their possession of their own DNA, which is circular and resembles bacterial DNA. Additionally, these organelles replicate independently of the cell cycle through a process similar to binary fission, akin to bacterial replication. Their ribosomes are also more similar to those of prokaryotes than to eukaryotic ribosomes, supporting the idea that they originated from ancestral prokaryotic cells.