What the HPQ??!! - Part 2
By analysing the genetics of dinosaurs and birds, I will be able to get a true indication of the heritage of birds and whether they are a part of the Dinosaur lineage. My initial idea in terms of investigation of the genetics, was based Dr. Mary Schweitzer’s remarkable discovery. She was able to find an iron containing compound called heme (part of haemoglobin that aids the red blood cell in carrying Oxygen), as well as remnants of nucleated red blood cells in the Tyrannosaurus Rex specimen MOR 1125. Nucleated red blood cells are found in all non-mammalian vertebrates, which provides evidence that organic matter like these are able to survive the process of fossilisation. It is possible however that Dr. Schweitzer’s specimen may have been sabotaged by the contamination of the microorganisms that produce the soft structures after fossilisation of the bone. The soft tissue could also just be biofilm, which is a self adherent layer of microorganisms combined with a slimy matrix (this helps them stick to the specific surface) which is produced by them. Matrix is a polymeric substance, meaning that it shares characteristics of the polymers, therefore matrix would possess high strength, high toughness and high resilience. Methods of Extraction A method that can be used to analyse the DNA of both Dinosaurs and Birds is electrophoresis. It is used to extract DNA or any charged molecules. It could for example be used for analysing the DNA of an Allosaurus and of a chicken. Plasma electrophoresis examines the globulins in the blood, which are a group of simple proteins soluble in saline solutions. It forms a large fraction of the blood serum protein. The process of electrophoresis for Rock Pigeon DNA includes the following steps: 1. Prepare the agarose gel in the casting tray 2. Remove the end blocks and the comb and submerge the gel under the buffer in the electrophoresis chamber 3. Place each sample of rock pigeon DNA in consecutive wells 4. Attach the safety cover and connect the leads to a power source and conduct electrophoresis 5. After electrophoresis, transfer the gel for staining 6. Analyze the gel by using a white light source. For step 4, the reason it is connected to a power source, is that the DNA samples are negatively charged and are ‘pulled’ to the other side of the agar tray, which is positively charged. We can use a Polymerase Chain Reaction (PCR) to make many copies of one piece of a specific DNA sequence. Thousands and Millions of copies are able to be made with the process of PCR. It can be used to examine Polymorphic (many forms) regions of DNA. These regions can vary in length for each individual (and organisms). They also fall into two categories 1. Variable Number of Tandem Repeats (VNTR) – A VNTR region contains 15 to 70 base pair sequences (with adenine, cytosine, guanine and thymine) which is repeated between 5 and 100 times. 2. Short Tandem Repeats (STR) – An STR region contains 15 to 70 base pair sequences (with adenine, cytosine, guanine and thymine) which is repeated with a length of 2 to 4 nucleotides. By investigating many different VNTR’s and STR’s from the same organism, we can gain an exclusive DNA profile of that organism, which is unique specifically to them. With this profile, we can compare this to the DNA, VNTR’s and STR’s of, for example, theropods like Allosaurus and Carcharadontosaurus. If Dr. Mary Schweitzer’s specimen of heme was copied using the Polymerase Chain Reaction technique, we could examine and observe it’s characteristics on a much larger scale, allowing us to compare a much larger collection of samples with the unique profile of the rock pigeon (or any other bird). By comparing both the dinosaurian and avian DNA using the techniques and methods above, we would be able to receive a clear indication into their propinquity in their lineage and heritage, hopefully proving their kinship. Once the tests have been conducted for VNTR’s and STR’s, then the comparison will be able to be conducted.