scientist have uncovered a critical character for rapid DNA repair in keep genome stability . A new field reveal that repair of double - strand break ( DSBs ) in nuclear DNA serve as a hefty guard against the desegregation of strange DNA from chloroplast — a phenomenon that , while important for evolution , can be highly destabilizing to the genome . The enquiry expands our cognition about plant genome evolution and also has relevancy to the medical theatre .
The findings , presented by Dr. Enrique Gonzalez - Duran and Prof. Dr. Ralph Bock from the Max Planck Institute of Molecular Plant Physiology in Nature Plants , exuviate young light on endosymbiotic gene transport ( EGT ) — an ongoing evolutionary process in which gene from organelles such as chloroplast and mitochondria are relocated into the atomic genome . While successful gene transfer assist the core to intimately organise its function with that of the organelles , they also pose risks : mutations arising by DNA interpolation can break up essential nuclear genes and chivy harmful rearrangement .
The team of researchers discovered that the DSB mend machinery has a key role in ensure the frequency of gene transfer . To inquire how plants control EGT , the team focus on the DSB hangout nerve pathway — known submission points for organellar DNA . Using genetically engineer tobacco plants and a previously developed screening system for EGT case , the research worker selectively inactivated two dissimilar DSB repair pathways and monitored over 650,000 seedling for new EGT issue .
The results were striking : disabling either of the two hangout pathways lead to a dramatic step-up in cistron transfers from chloroplasts to the cell nucleus — in some cases up to 20 - folding .
The researchers offer a Modern model to explain their resultant role : Under normal experimental condition , plant chop-chop fix DSBs in their nuclear deoxyribonucleic acid , efficaciously seal these vulnerable internet site before organellar DNA can infix . In this way , the DNA repair machinery serves as a molecular " gatekeeper " . However , when one repair pathway is defective , the other footpath can compensate to some extent , but repair proceed more slowly . This holdup leave DSBs exposed for recollective , thus creating more opportunity for chloroplast DNA to integrate . The resultant is a surge in EGT events , often accompanied by genome rearrangement and increased imbalance . " The magnitude of the consequence suggests that speedy DNA repair is substantive for plants to maintain long - full term genome stableness , " explains Dr. Enrique Gonzalez - Duran , first author of the study .
Although the work was carried out in tobacco plant , the team trust the mechanism unveil is likely universal across eukaryotes . " These DNA resort nerve tract are conserved in animals and fungi , " says Prof. Dr. Ralph Bock , managing director of the institute and co - author . " Our findings could explain like genome instability mechanisms in other organisms , including humans . Further enquiry is need to clarify this . "
The research opens raw avenues for understanding how organellar DNA conduce to genetic mutation in the nuclear genome . It may even have relevance for human health , and in fussy to cancer biology , where mitochondrial DNA insertions and genome instability are known molecular triggers of tumour initiation .
" Our discovery provides rudimentary perceptiveness into genome protection and the risks of factor transfer , " adds Gonzalez - Duran . " It reveals how crucial fast DNA repair is — not just to fix harm , but also to maintain the integrity of the genome itself . "
For more information : Max Planck Institute of Molecular Plant Physiologywww.mpimp-golm.mpg.de
