Login

News

Behavioral Genetics Models

Posted on
No user picture. George Richardson Joined: 10/18/2018

Sex Limitation Model Question

Forums
Behavioral Genetics Models
Hi,
I attended the Boulder workshop a couple years ago and am now trying my hand at sex limitation modeling. Currently, I am working on a same-sex twin pair sex limitation model for liability to alcohol use disorder. I've found measurement invariance and A and C are invariant. C was non-sig. and is constrained to zero. The AUD factor intercept is invariant. Can I interpret the sex difference in the AUD means in terms of greater genetic risk for AUD in the males?

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

ACE including non-twin siblings

Forums
Behavioral Genetics Models
Dear all,

I'm trying to adapt ACE heritability model to include both twins and their non-twin siblings. The data used for the analysis are imaging-derived phenotypes from the human connectome project (HCP) which includes both MZ and DZ twin pairs as well as their non-twin siblings for a subset of twins. Would be really helpful if anyone could answer a few questions.

Posted on
No user picture. sealx017 Joined: 08/17/2018

Multivariate cholesky model

Forums
Behavioral Genetics Models
Hi,

I have a dataset of twins on 4 time-points. I can fit the Multivariate cholesky decompositon model with ACE components. It considers unstrcutured covariance matrices for A, C and E component. I was wondering if its possible to restrict it to a special structure? Like, say compound symmetric or AR1.

Thanks

Posted on
No user picture. Cuttlefish Joined: 09/12/2018

Different age (covariate) for siblings

Forums
Behavioral Genetics Models
Dear all,
I’m working on the bivariate ACE model from 2016 Boulder workshop from Hermione Maes ‘twoSATja’ and ‘twoACEja’ (http://ibg.colorado.edu/cdrom2016/maes/UnivariateAnalysis/scriptsOpenMx.shtml). I use questionnaire data and some participants filled this out one or two years later than their twin siblings, this means that some siblings differ in age. How do I adjust the model to allow different ages between twins? I keep running into problems with non-conforming arrays…

Below the parts of the script that I have trouble adapting:

Posted on
No user picture. massimiliano.orri Joined: 06/11/2018

Latent Growth Model and distal outcome

Forums
Behavioral Genetics Models
Hi,
I would like to fit the twin model in the enclosed figure, but I am not sure if this is feasible.
Can someone help me understanding if the model is identified?
In case, are there any exemples of R code for this model?
Thanks a lot
M
Posted on
No user picture. sealx017 Joined: 08/17/2018

Include covariates in multivariate cholesky model

Forums
Behavioral Genetics Models

Hi,

I have a dataset of twins on 4 time-points and a covariate which does not vary over time. I can fit the Multivariate cholesky decompositon model with ACE components but stuck at the case where I want to include that covariate at each time-point.

This how I was including the covariate (snp),

defSNP <- mxMatrix( type="Full", nrow=1, ncol=2, free=FALSE, labels=c("data.snp1","data.snp2"), name="snp" ) {note that snp1 corresponds to twin 1 and snp2 corresponds to twin 2)

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

Constraining results of an algebra

Forums
Behavioral Genetics Models
Hi!

I am trying to constrain the results of an algebra, either to a fixed value or constraining the results of two algebras to be equivalent. I am using https://openmx.ssri.psu.edu//wiki/mxConstraint-help as a starting point.

Example output is attached, but the relevant lines of code are below

I want to fix AlCO[2,2] to 0 in the first example.

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

Moderation doubt

Forums
Behavioral Genetics Models
Hi everyone,
I am trying to test if there is a difference in one variable (quantitative) due to another variable (binary but different for each twin).
These variables are related and I want to test if there are different “subtypes” of that disorder (quantitative variable) depending on the value of the other variable (binary variable).
I was thinking to do a moderation analysis (as Rob suggested me in a previous post) as follows:
1-Quantitate variable
Posted on
No user picture. IvanVoronin Joined: 08/18/2013

Equality constraints in saturated model

Forums
Behavioral Genetics Models
What is the better way to introduce the constrains given that the constrained elements are computed, not defined as matrices?
Posted on
No user picture. szellers Joined: 04/04/2018

Diagnostics for Confidence Intervals

Forums
Behavioral Genetics Models
I am estimating a linear latent growth model using two twin samples and I am also estimating a common pathway model in the same samples. The latent slope and intercept are free to correlate with each other and with the latent factor from the common path model. I am trying to compute confidence intervals using mxCI and I am getting errors. When I use the verbose summary, I get the diagnostic and status code of "alpha level not reached iteration limit/blue" on many of my estimates. I've looked around at some documentation/other forum posts.
Subscribe to Behavioral Genetics Models
  Login

News