They were lifted out of the ocean as part of the accretionary wedge of an ancient subduction zone. The sedimentary and metamorphic rocks across the fault line are similar to those found in Redwood National and State Parks on the North Coast of California. They have been transported about 300 miles (500 kilometers) in a north-northwestward direction along the transform plate boundary. The granite rocks in the foreground are similar to those found in Yosemite National Park in the Sierra Nevada Mountains. Tomales Bay is the surface expression of the San Andreas Fault, seen in the photo below. Point Reyes National Seashore, California. Lateral Movement along a Transform Plate Boundary Virgin Islands is located on another transform plate boundary, where the Caribbean Plate is sliding past the oceanic part of the North American Plate. The landscapes of Channel Islands National Park, Pinnacles National Park, Point Reyes National Seashore and many other NPS sites in California are products of such a broad zone of deformation, where the Pacific Plate moves north-northwestward past the rest of North America. Perhaps nowhere on Earth is such a landscape more dramatically displayed than along the San Andreas Fault in western California. The grinding action between the plates at a transform plate boundary results in shallow earthquakes, large lateral displacement of rock, and a broad zone of crustal deformation. ![]() Such boundaries are called transform plate boundaries because they connect other plate boundaries in various combinations, transforming the site of plate motion. Instead, blocks of crust are torn apart in a broad zone of shearing between the two plates. In almost all cases you would be using one of these well characterized strains and so would not need to worry about whether there were unknown plasmids.Where tectonic plates slip horizontally past one another, lithosphere is neither created nor destroyed. coli) that have been studied for decades. In practice microbiologists have domesticated strains of bacteria (a favorite is Escherichia coli - often abbreviated to E. This is easy to test - we just try growing the bacteria in the presence of ampicillin, if they don't then we can use our plasmid. All we need to know is that the bacteria were are transforming are not already resistant to ampicillin. However this doesn't matter as much as you might think.įor example, assume we are using a plasmid that contains a marker (selectable gene) encoding resistance to ampicillin. We could sequence all the DNA inside the bacteria, but that is still a lot of work. It could be difficult to know if you were just using a random bacteria isolated from nature - especially since there are likely to be many thousands of different plasmids (1730 were present in a sequence database as of 2009). §Note: Polymerase chain reaction - you can learn more about this technique here: ‡Note: For some applications this can be very important, for example if you are using an expression vector you need the insert to transcribed in the correct direction! †Note: There are hundreds of commercially available restriction enzymes recognizing many different sequences (many of which are palindromes, but not all).Īmong these the most commonly used are six-cutters (with 6 bp recognition sites - if you make a bunch of simplifying assumptions you can calculate that these enzymes on average will cut once every 4096 bp. There are many more tricks that have been developed, but adding sites at the ends of primers almost always works, so that is a very good one to know! This amplifies the insert you want and creates a copy of the insert DNA with whatever restriction sites you want added at the ends. If the regions flanking the sequence you want to clone don't contain any useful restriction sites you can instead use primers with restriction sites added to their 5' ends and then amplify the sequence using PCR§. This again greatly increases the number of possible restriction enzyme sites. the different ends mean the insert can only be put into the plasmid in one orientation‡. In fact, it is quite common to use two different enzymes and this allows us to do "directional cloning" - i.e. Third, we don't need to use the same enzyme for both ends. Second, we often don't care if we clone a small amount of extra DNA, this means that we can search over a larger area than you might expect to find appropriate restriction enzymes. First, most vectors will have a region known as the "Multiple Cloning Site" (MCS) that can be cut with many different restriction enzymes† - this gives you more choices of enzyme and makes it more likely that you can find one that cuts near the ends of the region you wish to clone.
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