thumb|Baby Melody Pondthumb|168px|Melody "Mels" Pondthumb|"The only water in the forest, is the river"Melody Pond is the daughter of Rory Williams and Amy Pond. She was conceived on the TARDIS while it was in flight. Exposure to the Time Vortex at such a vulnerable stage altered her DNA the way it altered the DNA of the Doctor's people. Also, Madame Kovarian (the eye patch woman who kidnapped Amy) purposely altered Melody's DNA while Melody was still developing inside Amy which enhanced the relatively minor effects caused by the exposure to the Time vortex through the TARDIS. These changes have given her abilities like the Doctor namely that she can regenerate.
Melody was kidnapped and brainwashed to kill the Doctor by Madame Kovarian (who worked for The Silence). She was later revealed to be Mels, Amy and Rory's childhood friend.
She regenerated into the woman known as 'River Song'. Paradoxically, this name was given to her by the Doctor because the Doctor knew her as River Song in her future and his past, meaning the name River Song was created for her because the name was created for her. A similar thing happens with the name Melody, as she was named originally after Amy and Rory's childhood friend who just so happened to be Melody Pond, Amy and Rory's daughter. Basically, she was named after herself.