! SCRIPT NAME	: TwinsOnly.mx  
! GOAL		: To evaluate best model for variance components
! DATA		: continuous
! INPUT		: raw data
! UNI/BI/MULTI	: uni
! DATA-GROUPS	: MZ DZ
! MEANS MODEL	: grand mean
! VARIANCE COVARIANCE MODEL(S)	 ACE  
!

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


#define nvar 1				! For every instance of the word nvar in the script, 
						! Mx reads 1. This corresponds to one phenotype to be analysed

G1: calculation group
 Data Calc NGroups=3

  Begin matrices;
     X Lower nvar nvar Free	! additive genetic path coefficient (standard deviation)
     Y Lower nvar nvar Free	! common environmental path coefficient (standard deviation)
     Z Lower nvar nvar Free	! unique environmental path coefficient (standard deviation) 
     H Full 1 1	fix			! .5 for dz cov A
     G Full 1 nvar  free		! grand mean phenotypes
  End matrices;

 Matrix H .5				! Matrix H is fixed and contains .5

  Begin algebra;
     A= X*X' ;			  	! additive genetic variance
     C= Y*Y' ;   			! common environmental variance
     E= Z*Z' ;				! unique environmental variance

     V = A%(A+C+E) | C%(A+C+E) | E%(A+C+E) ;	    ! standardized variance components
  End algebra;

st -.8 G 1 1 1 
st 10 X 1 1 1 - X 1 nvar nvar
st 1 Y 1 1 1 - Y 1 nvar nvar 
st 8 Z 1 1 1 - Z 1 nvar nvar

end

G2: MZ twins, datagroup
 Data NInput_vars=34
 Missing=-200.00
 REctangular file=mriiq.rec
 LABELS  
  famnr zyg 
  sex1 age1 wmem1 grey1 	
  sex2 age2 wmem2 grey2		
  sex3 age3 wmem3 grey3		
  sex4 age4 wmem4 grey4		
  sex5 age5 wmem5 grey5		
  sex6 age6 wmem6 grey6		
  sex7 age7 wmem7 grey7		
  sex8 age8 wmem8 grey8		
  
 select if zyg < 3 ; 			! Zyg = 1=mzm, 2=mzf, 3=dzm, 4=dzf, 5=dos

select   
wmem1 
wmem2   ; 
Matrices = Group 1
End Matrices

     Means G | G ;			! model for means, assuming grand mean twin 1 = grand mean twin 2
     Covariances			! model for MZ variance/covariances
	A+C+E	| A+C	 _
	A+C	| A+C+E	;

Options RSiduals
End

G3: DZ twins, datagroup
 Data NInput_vars=34
 Missing=-200.00
 REctangular file=mriiq.rec
 LABELS
 famnr zyg 
  sex1 age1 wmem1 grey1 	
  sex2 age2 wmem2 grey2		
  sex3 age3 wmem3 grey3		
  sex4 age4 wmem4 grey4		
  sex5 age5 wmem5 grey5		
  sex6 age6 wmem6 grey6		
  sex7 age7 wmem7 grey7		
  sex8 age8 wmem8 grey8		
  
 select if zyg > 2 ; 			! Zyg = 1=mzm, 2=mzf, 3=dzm, 4=dzf, 5=dos

select   
wmem1 
wmem2   ; 
Matrices = Group 1
End Matrices

     Means G | G;			! model for means, assuming grand mean twin 1 = grand mean twin 2
     Covariances			! model for MZ variance/covariances
	A+C+E	| H@A+C	 _
	H@A+C	| A+C+E	;

 Options RSiduals
 !Interval @95 V 1 1 1 V 1 1 2 V 1 1 3
End