Abstract :
[en] We studied the mtDNA bottleneck in zebrafish to elucidate size, timing, and variation in germline and non-germline cells. Mature zebrafish oocytes contain, on average, 19.0 3 106 mtDNA molecules with high variation between oocytes. During embryo- genesis, the mtDNA copy number decreases to $170 mtDNA molecules per primordial germ cell (PGC), a number similar to that in mammals, and to $50 per non-PGC. These occur at the same developmental stage, implying considerable variation in mtDNA copy number in (non-)PGCs of the same female, dictated by variation in the mature oocyte. The pres- ence of oocytes with low mtDNA numbers, if similar in humans, could explain how (de novo) mutations can reach high mutation loads within a single gener- ation. High mtDNA copy numbers in mature oocytes are established by mtDNA replication during oocyte development. Bottleneck differences between germ- line and non-germline cells, due to early differentia- tion of PGCs, may account for different distribution patterns of familial mutations.
Scopus citations®
without self-citations
39