Mitochondrial DNA (mtDNA) has a unique type of inheritance. It is passed directly from mother to child, and it accumulates changes much more slowly than other types of DNA. Due to its unique characteristics, mtDNA has provided valuable information on evolutionary history. For example, differences in mtDNA is considered to assess how closely one species to another. Analysis of mitochondrial DNA from people around the world have shown a lot of clues about ancient human migration patterns. Conditions on Earth 4 billion years ago were very different than they are today. The atmosphere lacks oxygen and ozone is not to protect the Earth from harmful radiation. Heavy rains, lightning and volcanic activity are common. However, early cell run in extreme conditions. Today, a group of unicellular organisms called archaea archaeabacteria or still thrive in extreme habitats. Astrobiolohy currently use archaea to study the origin of life on Earth and other planets. Because archaea living areas previously considered incompatible with life, they may contain information that will improve our ability to detect extraterrestrial life. Interestingly, current studies show that archaea may be capable of space travel result of a meteorite. This event may have sown life on Earth or elsewhere strattera no prescritpion. Archaea survive today in very difficult conditions, such as salt evaporation ponds at the edge of the Great Salt Lake (see above) and boiling hot springs Yellowstone National Park (right). .
