The gene that I have choosen to research is called tryptophan hydroxylase 2 (TPH2). It is also sometimes known as NTPH or ADHD7. TPH2 is a protein coding gene that codes for a protein known as tryptophan 5-hydroxylase 2. It is also sometimes known as neuronal tryptophan hydroxylase or tryptophan 5-monooxygenase 2.In humans, this protein is responsible for catalysing the first and rate limiting step in the production of serotonin, which is an important neurotransmitter and hormone. Mutations in the protein-producing gene can be associated with psychiatric diseases, including but not limited to major depression and bipolar affective disorder, as well as attention deficit-hyperactivity disorder 7 (ADHD7) and tryptophan 5-monooxygenase deficiency.I expect that I should be able to find this protein in other organisms due to the fact that the protein-coding gene is not exclusively found in humans. It can also be found in chimpanzees, Rhesus monkeys, dogs, mice, rats, chickens, frogs, and other organisms, and therefore I can also expect find the protein in those organisms, though this may not always be true.You might not find the protein produced by a gene in one organism in every organism with that gene. Due to gene activation and deactivation, a gene may not express the same in every organism, and therefore would not code for the same protein. Another reason you might not find the protein is because of mutations. Not all organisms are the same, and therefore not all organisms need the same proteins. If an organism doesn’t need the protein, it may adapt, or mutate, so that the gene is able to produce a different, needed protein.If the same gene is present in all of the organisms I’ve tested, it would mean that, in the history of life, it has been successful in performing its job. The main reason that all organisms would have the same gene would be that the gene is in someway neither necessary or useful in assisting in survival on Earth. It suggests that the gene has evolved to be used in all species and has an important purpose.The use of DNA sequences when studying evolutionary relationships does not mean that all other characteristics aren’t important. Even though you can get very accurate representations of evolution from DNA, you can find additional, potentially helpful information from observing physical characteristics. Additionally, these studies are not always completely accurate, and physical characteristic can help confirm accuracy by cross referencing them with the DNA traits to see if the phenotypes match.