This family tree is the work of Bruno Ceriotti. Help in putting this together has been provided by John H Warburg and Steve Rogers, to whom I'm most grateful.
YES #1 (AUG 1, 1968 - SEPT 22, 1968)
1) Peter William Brockbanks (aka Peter Banks) vocals, lead guitar
2) Christopher Russell Edward 'Chris' Squire vocals, bass, piano
3) John Roy 'Jon' Anderson lead vocals, tamburine, harmonica, percussion
4) William Scott' Bill' Bruford drums
5) Anthony John Selridge (aka Tony Kaye) organ, piano
YES #2 (SEPT 23, 1968 - SEPT 27, 1968)
1) Peter Banks
2) Chris Squire
3) Jon Anderson
4) Tony Kaye
5) Dave Potts drums
YES #3 (SEPT 28, 1968 - NOV 23, 1968)
1) Peter Banks
2) Chris Squire
3) Jon Anderson
4) Tony Kaye
5) Tony O'Reilly drums
+
6) Ian Wallace drums (filled in for Tony for one gig in November)
6) Ian Wallace drums (filled in for Tony for one gig in November)
YES #4 (aka #1) (NOV 24, 1968 - APR 18, 1970)
1) Peter Banks
2) Chris Squire
3) Jon Anderson
4) Tony Kaye
5) Bill Bruford
YES #5 (APR 19, 1970 - JUL 1970)
1) Jon Anderson
2) Bill Bruford
3) Chris Squire
4) Tony Kaye
YES #6 (JUL 1970 - JUL 31, 1971)
1) Jon Anderson
2) Chris Squire
3) Tony Kaye
4) Bill Bruford
5) Stephen James 'Steve' Howe vocals, lead guitar, acoustic guitar
YES #7 (AUG 1, 1971 - JUL 19, 1972)
1) Jon Anderson
2) Chris Squire
3) Bill Bruford
4) Steve Howe
5) Richard Christopher 'Rick' Wakeman organ, piano, mellotron, synthetizer
YES #8 (JUL 20, 1972 - MAY 18, 1974)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Rick Wakeman
5) Alan White drums, percussion, vocals
YES #9 (MAY 19, 1974 - AUG 6, 1974)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
YES #10 (AUG 7, 1974 - OCT 1976)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
5) Patrick Phillipe Moraz keyboards
YES #11 (aka #9) (OCT 1976 - NOV 1976)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
YES #12 (aka # 8) (NOV 1976 - JAN 1980)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
5) Rick Wakeman
YES #13 (JAN 1980 - FEB 1980)
1) Chris Squire
2) Steve Howe
3) Alan White
YES #14 (FEB 1980 - DEC 1980)
1) Chris Squire
2) Steve Howe
3) Alan White
4) Geoffrey 'Geoff' Downes keyboards
5) Trevor Charles Horn bass, guitar
YES #15 (JUN 1983 - OCT 1983)
1) Jon Anderson
2) Chris Squire
3) Alan White
4) Tony Kaye
4) Tony Kaye
5) Trevor Charles Rabinowitz (aka Trevor Rabin) guitar
YES #16 (OCT 1983 - JAN 1984)
1) Jon Anderson
2) Chris Squire
3) Alan White
4) Trevor Rabin
5) Edwin 'Eddie' Jobson keyboards
YES #17 (aka #15) (JAN 1984 - SEPT 1988)
1) Jon Anderson
2) Chris Squire
3) Alan White
4) Trevor Rabin
5) Tony Kaye
YES #18 (EARLY 1991 - MAR 5, 1992)
YES #16 (OCT 1983 - JAN 1984)
1) Jon Anderson
2) Chris Squire
3) Alan White
4) Trevor Rabin
5) Edwin 'Eddie' Jobson keyboards
YES #17 (aka #15) (JAN 1984 - SEPT 1988)
1) Jon Anderson
2) Chris Squire
3) Alan White
4) Trevor Rabin
5) Tony Kaye
YES #18 (EARLY 1991 - MAR 5, 1992)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Rick Wakeman
5) Bill Bruford
6) Tony Kaye
7) Trevor Rabin
8) Alan White
YES #19 (aka #15, #17) (SPRING 1994 - OCT 11, 1994)
1) Jon Anderson
2) Chris Squire
3) Tony Kaye
4) Alan White
5) Trevor Rabin
YES #20 (aka #8, #12) (MAR 4, 1996 - 1997)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Rick Wakeman
5) Alan White
YES #21 (1997 - MAR 25, 2000)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
5) William Wyman 'Billy' Sherwood keyboards, bass, guitar
6) Igor Khoroshev keyboards
YES #22 (MAR 26, 2000 - AUG 4, 2000)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
5) Igor Khoroshev
YES #23 (aka #9, #11) (AUG 5, 2000 - JUL 21, 2001)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
YES #24 (JUL 22, 2001 - DEC 13, 2001)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
5) Tom Brislin keyboards, vocals
YES #25 (aka #9, #11, #23) (DEC 14, 2001 - APR 2002)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
YES #26 (aka #8, #12, #20) (APR 2002 - SEPT 22, 2004)
YES #23 (aka #9, #11) (AUG 5, 2000 - JUL 21, 2001)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
YES #24 (JUL 22, 2001 - DEC 13, 2001)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
5) Tom Brislin keyboards, vocals
YES #25 (aka #9, #11, #23) (DEC 14, 2001 - APR 2002)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
YES #26 (aka #8, #12, #20) (APR 2002 - SEPT 22, 2004)
1) Jon Anderson
2) Chris Squire
3) Steve Howe
4) Alan White
5) Rick Wakeman
YES #27 (2008)
1) Jon Anderson
2) Chris Squire
2) Steve Howe
4) Alan White
5) Oliver Wakeman keyboards (Rick's son)
YES #28 (2008 - JAN 2011)
1) Chris Squire
2) Steve Howe
3) Alan White
4) Oliver Wakeman
5) Benoit David vocals
YES #29 (JAN 2011 - FEB 5, 2012)
1) Alan White
2) Chris Squire
3) Steve Howe
4) Geoff Downes
5) Benoit David
YES #30 (FEB 6, 2012 - MAY 2015)
1) Alan White
2) Chris Squire
3) Steve Howe
4) Geoff Downes
5) Jon 'Juano' Davison vocals
YES #31 (MAY 2015 - PRESENT)
1) Alan White
2) Billy Sherwood
3) Steve Howe
4) Geoff Downes
5) Jon Davison
+
7) Jay Schellen drums (filled in for Alan White from time to time since summer 2016)
YES #27 (2008)
1) Jon Anderson
2) Chris Squire
2) Steve Howe
4) Alan White
5) Oliver Wakeman keyboards (Rick's son)
YES #28 (2008 - JAN 2011)
1) Chris Squire
2) Steve Howe
3) Alan White
4) Oliver Wakeman
5) Benoit David vocals
YES #29 (JAN 2011 - FEB 5, 2012)
1) Alan White
2) Chris Squire
3) Steve Howe
4) Geoff Downes
5) Benoit David
YES #30 (FEB 6, 2012 - MAY 2015)
1) Alan White
2) Chris Squire
3) Steve Howe
4) Geoff Downes
5) Jon 'Juano' Davison vocals
YES #31 (MAY 2015 - PRESENT)
1) Alan White
2) Billy Sherwood
3) Steve Howe
4) Geoff Downes
5) Jon Davison
+
7) Jay Schellen drums (filled in for Alan White from time to time since summer 2016)