Is Amy in Sonic the Hedgehog sonics sister?

Amy is a pink female hedgehog who is closely involved with Sonic, first appearing in Sonic CD(1993), Amy has expressed a great fondness for Sonic, eventually in the series, namely Sonic Adventure(1999) Amy has begun to expressed her love for him, even to the point of her believing that she is his girlfriend and from there it was always maintained by her character, that she would follow by his side, much to Sonic's very own dismay over the subject itself.

However, in the animated television show Sonic Underground (1999), Sonic had a twin sister named Sonia who in many ways was much like Amy in appearance and personality, if not to a slightly lesser extent -- Amy isn't Sonic's sister.