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Behavioral Genetics Models

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No user picture. Aurina Joined: 01/05/2016

Including covariates to saturated model

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Behavioral Genetics Models
Hello,

I'm trying to run an ACE model for some imaging-derived measures and hope you could help me to solve some of the issues.

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No user picture. szellers Joined: 04/04/2018

Latent Growth Curves and Definition Variables in a Twin Sample

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Behavioral Genetics Models
I am trying to fit a latent growth model in twin data and I am having trouble writing code for definition variables. I want to fix the loading from the intercept to the observed vars to 1 and I want to use age at assessment as the loading for the slope. This model runs when I use just a number corresponding to wave (1, 2, 3, 4, 5) for the slope loadings, but I am having errors when trying to use the definition variable of age at each assessment as the factor loading for the slope. My code here fails at the flValues line.

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No user picture. JuanJMV Joined: 07/20/2016

Longitudinal Question

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Behavioral Genetics Models
Hi,

I am considering using a bivariate model to investigate the relationship between variable 1 and variable 2. Data is available for both variables for the same population for 2010 and 2016.

If I want to investigate this relationship longitudinally (the effect of variable 1 on variable 2) could I use a bivariate script with variable 1 in 2010 and variable 2 in 2016? or should I use a different model/script?

Thank you so much.

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No user picture. lior abramson Joined: 07/21/2017

Bivariate Cholesky model with paths specification

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Behavioral Genetics Models
Dear Forum,
I wrote a syntax for bivariate cholesky model for two variables measuring two different traits at the same time-point. However, I think that I may have missed something. In the output I see the ACE coefficients for each observed variable, but I do not see the the ACE coefficients to the covariance between the two traits (i.e. the coefficients that explain what part of the variance is explained by shared genetic and environmental influences on the two traits).

Do you know what I should add to the syntax in order to receive this output?

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No user picture. Fengxia Joined: 11/02/2017

Bivariate twin model（ACEorADE）

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Behavioral Genetics Models
Hello,

Recently, I have done a bivariate models.BUT I am confused with how to choose ACE or ADE in the bivariate models? I have tried using ICC in each variable apartly, BUT the fitting model one is ACE when another is ADE. NOW the question is that which one bivariate model I should use ? ACE-ACE or ADE-ADE or ACE-ADE? If the the answer is ACE-ADE, how to write the script?

Thanks for some help!

Cheers,
Fengxia

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No user picture. oscarrob Joined: 03/10/2018

Twins raised apart + together

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Behavioral Genetics Models
Ciao all,

I do not know if this is the most appropriate section for posting however I will give it my best shot. I am conducting a capstone project for my genetic epidemiology program but unfortunately my mentors are unaware of the methods used for the project I will describe here so they encouraged me to connect with individuals on this website. Some may argue I should do a project that I can receive some assistance with from my mentors but I am passionate about this project!

Posted on
No user picture. JBosdriesz Joined: 03/07/2017

Multiple testing

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Behavioral Genetics Models
One of my Phd students recently received reviewer comments for a submitted paper in which she presented 9 univariate ACE models on separate outcome measures. One of the reviewers asked: “Please indicate how correction for multiple comparisons was handled for the genetic modeling. Given that several brain regions were being analyzed, what statistical threshold was used?”
First of all, is any such correction really needed for 9 outcomes?
Posted on
No user picture. JuanJMV Joined: 07/20/2016

doubt with binary variables

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Behavioral Genetics Models
Hi everyone,

I am trying to do a joint analysis between 2 binary variables and 1 continuous variable I am having some problems to fix the variance for the 2 binary variables equal 1.

I think I should change something here

matUnv <- mxMatrix( type="Unit", nrow=nvo, ncol=1, name="Unv1" )
matOc <- mxMatrix( type="Full", nrow=1, ncol=nv, free=FALSE, values=oc, name="Oc" )
var1 <- mxConstraint( expression=diag2vec(Oc%&%V)==Unv1, name="Var1" )

NVO=2
NV=3

Posted on
Picture of user. chancey Joined: 09/09/2017

Rationale for Bootstrapping CIs

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Behavioral Genetics Models
Hi all,

Is there a rationale for bootstrapping 95% CIs for univariate ACE estimates when relying on a relatively small convenience sample of MZ/DZ twins? Any source(s) that would support doing so?

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No user picture. JuanJMV Joined: 07/20/2016

Moderation Model

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Behavioral Genetics Models
Hi everyone,

I am trying to fit a moderation model. I have modified one script but in this script the moderation variable is the same for twin1 and twin 2 (age). I want to fit a moderation model with 1 variable with different values for twin1 and twin2 (like IQ). I have done all the changes but I am not sure if it is correct. Specially this line:

meanG <- mxAlgebra( expression= cbind((int + DR1),(int + DR2)), name="expMeanG" )

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