Jonas’s gift is the capacity to see beyond. This means he can see things that are not part of the regular world of the community, such as color. He also has the ability to receive memories, which exist beyond the community. We are first told what this ability is during the Ceremony of Twelve when the Chief Elder explains why Jonas was selected to be Receiver of Memory.
The author foreshadows this ability in the incident with the apple. Jonas notices the apple change, and takes it home to look at it even if it is against the rules. He looks at it, tosses it, and tries to figure out what is different about it. Jonas is seeing the color red, but he does not know it yet. He is reprimanded for taking the apple, but the incident with the apple demonstrates to the elders that he really does have the capacity to see beyond.