Computational Biology Center, IBM TJ Watson Research, Yorktown Heights, NY 10598, USA.|Computational Biology Center, IBM TJ Watson Research, Yorktown Heights, NY 10598, USA.|Computational Biology Center, IBM TJ Watson Research, Yorktown Heights, NY 10598, USA.|Computational Biology Center, IBM TJ Watson Research, Yorktown Heights, NY 10598, USA.|Computational Biology Center, IBM TJ Watson Research, Yorktown Heights, NY 10598, USA.