From the article: "These objects have the potential to yield DNA, specifically what is known as 'touch DNA','" Ric Gillespie, executive director of The International Group for Historic Aircraft Recovery (TIGHAR), told Discovery News in an email interview from Nikumaroro."
The researchers have samples of "reference" DNA from the Earhart that they hope to compare with. If this is the case that means that its likely Earhart (and possibly her navigator, Fred Noonan) actually survived their plane crash and died on a remote island.
A few years ago another piece of evidence was found as well. Originally thought to be a turtle's bone, below is a picture that is now thought by researchers to be one of Earhart's finger bones.
In the 1940's parts of a skeleton (along with other artifacts including a shoe) of what was thought to be a female of Northern European descent within range of the build/height of Earhart was found, but those bones have ended up going lost. One of the problems with finding remains there, are the island's famous huge Coconut crabs. During researcher-led tests a Pig's body was laid down and within 10 minutes was dismembered and spread out all over the island. She wouldn't have stood a chance.
There are many conspiracy theorists with notions of her disappearance involving everything from her being a WWII spy against the Japanese, she was shot down and captured by the Japanese, she disappeared intentionally, she changed her identity,
Source links -> http://news.discovery.com/history/amelia-earhart-island-artifacts.html