In Science this week, a multi-institute team of scientists in the UK presents a study that shows how human mitochondrial DNA is influenced by the nuclear genome. The researchers performed whole-genome sequencing of the mtDNA of nearly 13,000 individuals, and found that roughly 45 percent of those from 1,526 mother-offspring pairs carry a mixed population of mtDNA. Over a single generation, they observed selection for and against variants in specific genomic regions, with known variants more likely to be transmitted than previously unknown variants. "However, new heteroplasmies were more likely to match the nuclear genetic ancestry as opposed to the ancestry of the mitochondrial genome on which the mutations occurred," the investigators write. "Thus, human mtDNA at the population level is shaped by selective forces within the female germ line under nuclear genetic control, which ensures consistency between the two independent genetic lineages."
And in Science Advances, a Mount Sinai-led group describes a new genomics-based platform that uses a common model organism to personalize colorectal cancer treatment. The researchers performed an extensive analysis of the genomic landscape in a tumor from a patient with KRAS-mutant metastatic colorectal cancer, identifying nine key disease drivers. They then created a transgenic Drosophila model with altered orthologs of these genes, which was used in a robotics-based screen to pinpoint a specific candidate drug combination. When treated with this cocktail, the patient experienced a significant response that included a reduction in target tumors and a stabilization of disease. The approach, the investigators write, can be adapted for other tumor types and may prove especially useful in tumors with challenging profiles.
The Daily Scan's sister site, GenomeWeb Daily News, has more on the study here.