Behavioral Genetics Models

Hello,

I'm quite new to twin modelling and have come across the following problem.

Before I run my proper model, I'm trying to account for any existing sex differences on the phonetypes of interest.
Am running the following model for each trait:

## Univariate sex-limitation ####RG is FREE####
#
unSexACEModel <- mxModel("unSexACE",
mxModel("ACE",
# ace path coefficients for males and females
mxMatrix("Lower", nrow=nv, ncol=nv, free=TRUE, values=0.2, label="am11", name="am"),

Hi,

Is it possible to use the twin ACE model with paired variables (only one value for each twin pair)?

Thank you!

I read the users' guide of Mx. The sample size and power can be calculated by Mx. But I haven't learned how to use MxGUI. Could OpenMx be used to calculate sample size and power?

I've used OpenMX to duplicate an MX model using bivariate Cholesky of alcohol use disorder symptoms (ordinal variable with 4 thresholds) and remission (bivariate). Results are similar but I cannot figure out how to test a submodel that equates male and female parameters on the threshold variables (first has 4 thresholds, second has just one). Any ideas? From what I've read OpenMX may still be a little dicey with ordinal variables? Script attached.

Hi all,

I have been working with OpenMx in R with some success over the past several months after attending the Boulder conference last March. The scripts provided at the workshop have been very helpful, but I can't seem to find examples for independent and common pathways models. Any help would be greatly appreciated.

Thanks,
JM

Hi, everyone.

I was fitting a multivariate model with a general script. The commands didn't have errors. After I mxRun() and summary() my model, it quickly presented the summary. But the problem was that there were no -2ll, AIC, BIC, or any other fitting results, though the number of observations was rightly showed. And it seemed just summarized the dataset, like the min, max, and mean of every variables of the dataset, not the model fit. I guess the values of the variables were not input to the model. But why?

Hi all,

I was fitting an bivariate ordinal model, after the use of mxFactor(), I made the variables into ordered factors, like this

maxthresh <- 2
mzData$smoking1=mxFactor(mzData$smoking1, levels= c(0:maxthresh))

. After I ran the saturated (or ACE) model, the error appeared. It said that

In model 'Saturated_Fit' 'the thresholds in column 'smoking1' are not in sorted order.

Can anyone tell me what the reason is? Thank you in advance.

Hi, everyone. I found that when construct submodels, such as AE or CE models, the usual commands are like this:

AEModel <- mxModel(ACEFit, name="AE",
mxModel(ACEFit$ACE,
mxMatrix( type="Lower", nrow=nv, ncol=nv, free=F, values=0, name="c" ) # drop c at 0
))

, not this:

AEModel <- mxModel(ACEModel, name="AE",
mxModel(ACEModel$ACE,
mxMatrix( type="Lower", nrow=nv, ncol=nv, free=F, values=0, name="c" ) # drop c at 0
))