The segregation of organelles and organellar genomes across eukaryotic biology

Eukaryotic cells are characterized by the presence of organelles such as mitochondria and, in the case of plants and certain protists, plastids, both of which often contain their own genomes. Accurate distribution of replicated organelles and their genomes to daughter cells is crucial for cell survival and propagation across all eukaryotic organisms. Unlike nuclear DNA, which follows a well-characterized segregation process via the mitotic spindle, organelle genomes are inherited through more diverse and less-understood mechanisms. Ensuring proper organelle genome inheritance is essential for maintaining cellular energy production, metabolic functions, and overall viability. Because organelle and organelle genome segregation lack a universal mechanism, different organisms employ various strategies that include stochastic distribution and active cytoskeletal transport and membrane tethering to prevent the loss of essential genetic material while supporting organelle division and turnover. This review provides an overview of organelle and organellar DNA segregation mechanisms in diverse eukaryotic systems before focusing on the tripartite attachment complex as a specialized adaptation in kinetoplastid parasites.