is it possible to find the same gene in two different kinds of organisms but not find the protein that is produced from that gene? why might this happen?

Explanation:There are many forces of evolution, one of which is gene mutation. Gene mutation leads to new forms of genes that might been favored in natural selection, but it can also lead to something called a "pseudogene". Pseudogenes are mutated forms of functional genes that have lost their protein coding ability. To quote part of a basic definition, "Pseudogenes often result from the accumulation of multiple mutations within a gene whose product is not required for the survival of the organism." They can be useful for determining evolutionary relation between two organisms if one organism contains a pseudogene version of a function protein-coding gene found in another organism.

To answer the second question, DNA is obviously very important in studying genetic relations, however other characteristics are still very important to consider. While there are shared characteristics that happen to evolve similarly that do not indicate genetic relation (such as the similar osteological anatomy of the wing bones of a bat, the fin of a whale, and the arm of a human) call analogous traits, there are still many things to be ascertained from physical similarities that are representations of genetic relation, called homologous traits.