Global Gene Project to Trace Humanity's Migrations

Global Gene Project to Trace Humanity's Migrations: "Tracking Genetic Markers

Each human parent contributes half of a child's DNA, which combines with the other parent's DNA to form a new genetic combination. This so-called recombination gives each of us a unique set of attributes: hair, eye, and skin color; athleticism or lack thereof; susceptibility to certain diseases; and so on.

However, the chunk of DNA known as the y chromosome, which only males possess, is passed from father to son without recombining. The y chromosome, therefore, remains basically unchanged through generations, except for random mutations. Similarly, women pass mitochondrial DNA, which also does not recombine, on to both their sons and daughters.

Random mutations to DNA, which happen naturally and are usually harmless, are called markers. Once a marker has been identified, geneticists can go back in time and trace it to the point at which it first occurred. This way, they are able to determine when and where a new lineage began. "