In English, "to prove" often means "to show something beyond doubt," as in "to prove a theorem in geometry," or "to prove guilt" in a court of law. However, it also has another range of meanings. "To prove something" can mean "to test something," "to try something out," or "to find out just how good something is." When DNA testing became available, everyone knew it would be useful, but nobody knew yet just how useful it would be. It might be just another helpful tool, or it might be a breakthrough, a "game changer" that would completely change the way wildlife crime investigation was done. When it was tried out, in actual practice, it proved to be more than just another tool. It proved to be a game changer. "Prove," meaning "to test" or "to try out" is an older meaning of the word. It's closely related to the Spanish "probar," and to the verb "to probe." We see the older meaning in a famous poem, "The Passionate Shepherd to his Love," by Christopher Marlowe in the late 1500s: "Come live with me and be my love, And we will all the pleasures prove." That is, "we'll try everything." It also occurs in the classic 1611 English translation of the Bible, the King James Version, 1 Thessalonians 5:21, "Prove all things; hold fast that which is good," which a modern translation renders as "but test them all; hold on to what is good."

"DNA analysis has proved a game changer in wildlife crime investigation." before DNA analysis was available to mankind, wildlife crime investigation was pretty tough and finding evidence was more of a hassle, but after availability of this analytical system, solving became much easier.. so here "game changer" mean it changed the way of solving matter..

I believe it is referring to the fact that research has determined that DNA analysis is doing something completely different for wildlife crime investigation. Basically it means that evidence has come to light with DNA analysis being useful in this context.

'proved a game-changer' is an idiomatic way of saying 'proved to be a game-changer', meaning that it turned out to be a game-changer, or that it eventually resulted in game-changing.

Thank you for the answers but is the phrase " has proved a game changer" by itself some idiom? I know the general meaning of the whole sentence, but this one phrase is hard for me to translate. (I may have titled my question wrong, sorry for that.)