why is the protien "p53" so important to humans, and what gene pool is it made in?

Answer 1

p53 has many different functions in the human cell. One of them is to respond to DNA damage and trigger a cell cycle arrest. That way it allows the cell to repair DNA damage before it divides.
Mutations in p53 are found in many different types of cancers.
Im not sure if I understand the second part of your question.

Answer 2

p53 is in the human gene pool...outside of that, I don't know. But, as the previous 2 answerers have pointed out, p53 is essential to the functioning of cell division, and it is one of the genes that, in general, (although not always), is found defective in certain types of cancerous cells.

Answer 3

p53, also known as protein 53 (TP53), is a transcription factor that regulates the cell cycle and hence functions as a tumor suppressor. It is important in multicellular organisms as it helps to suppress cancer. p53 has been described as "the guardian of the genome", "the guardian angel gene", or the "master watchman", referring to its role in conserving stability by preventing genome mutation.[1]

The name p53 is in reference to its apparent molecular mass: it runs as a 53-kilodalton (kDa) protein on SDS-PAGE. Its theoretical molecular mass, based on the sum of its amino acid residues, is in fact only 43.7 kilodaltons. This difference is due to the high number of amino-acid proline residues in the p53 protein which slow p53's migration on SDS-PAGE, thus making it appear larger. This observation is also seen in p53 from other species including rodents, frogs, and fish.