outstanding biology questions

DNA testing can reveal how closely related you are to a group of people halfway around the world or, if you're doing evolutionary research, where organisms fit on taxonomic trees. The same DNA tests, when performed on the cells in a single human body, can be used to reconstruct lineage trees that can trace the cells' ancestry back to the embryo. The principle in all three cases is the same: DNA amasses mutations over time, and these mutations can be used to assess how far back two people, organisms or cells shared a common parent. The idea for the cell lineage trees comes from the group of…