Medical Genetics 2. mtDNA replication Both strands of mammalian mtDNA are synthesized continuously as leading strands synthesis of the first mtDNA strand proceeds partially auses, and is then completed upon receipt of appropriate signals. The result is that most mtDNA has D-loops Synthesis of the second strand is initiated after the fork synthesizing the first strand passes the origin of second strand synthesis. During plastid DNA replication RNA primers are incompletely excised and replaced as a result the plastid genome is a chimeric DNA-RNA molecule. Origins of plastid DNA replication have been identified TWO D-loops are found in plastid dNa They represent initiation on opposite DNA strandsMedical Genetics 2. mtDNA replication • Both strands of mammalian mtDNA are synthesized continuously as leading strands. • Synthesis of the first mtDNA strand proceeds partially, pauses, and is then completed upon receipt of appropriate signals. The result is that most mtDNA has D-loops. • Synthesis of the second strand is initiated after the fork synthesizing the first strand passes the origin of second strand synthesis. • During plastid DNA replication RNA primers are incompletely excised and replaced. As a result the plastid genome is a chimeric DNA-RNA molecule. Origins of plastid DNA replication have been identified. • Two D-loops are found in plastid DNA. They represent initiation on opposite DNA strands