Segregation, mtDNA

At the time of cell division, the proportion of mutant and wild-type mtDNAs in the two daughter cells can shift, thus giving them different genotypes and, possibly, different phenotypes, a phenomenon called mitotic segregation. 

Transmission by Maternal Inheritance and Random Segregation of mtDNA during... 

There are several limitations in using primary cell lines from patients with mitochondrial disease (e.g., fibroblasts and myoblasts) (Jl). They are not immortal, and usually grow very slowly in regular culture media. Some of the cell lines do not retain a fully physiological, differentiated phenotype in culture. In addition, they tend to lose mutant mtDNA as a result of mitotic segregation (Jl). Most importantly, one cannot rule out the effect of the nuclear background on the phenotypic expression of mitochondrial dysfunction under examination. 

Til. Trounce, I., Neill, S., and Wallace, D. C., Cytoplasmic transfer of the mtDNA nt 8993 T-G (ATP 6) point mutation associated with Leigh syndrome into mtDNA-less cells demonstrates co-segregation with a decrease in state III respiration and ADP/O ratio. Proc. Natl. Acad. Sci. USA 91, 8334-8338 (1994). 

The genetics of mutations in mtDNA are defined by maternal inheritance, replicative segregation, threshold expression, a high mtDNA mutation rate, and the accumulation of somatic mutations with age. The maternal inheritance pattern reflects the exclusive transmission of mtDNA from the mother to her children. The egg contains approximately 300,000 molecules of mtDNA packaged into mitochondria. These are... 

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