Behavioral Genetics Models

Hi,
I am new to Twin data analysis and would like to get help on the bivariate genetic analysis. I want to calculate the genetic correlations between two traits in twins. However, I only found the scripts about the univariate twin analysis in documentations. How can I get the bivariate ACE model in OpenMX?

Thank you

I have fit two saturated models and have created correlation matrices from the expected covariance matrices using the cov2cor function. I would like to constrain the correlation matrices to equality between these models without constraining the covariance matrices.

We have 7 variables, of which one of the variable is significantly heritable - modeled using univariate analyses. Is it theoretically congruent to test for shared genetics between all 7 variables using the correlated factors model despite the fact that 6 of the variables are not significantly heritable?

Hi,

I'm attempting to run a BG script of an independent pathways model on 9 dichotomous (symptom) manifest variables. That is, the model includes biometric factors specific to each manifest variable and common to all manifest variables. I've been able to get this model to run without any problems.

Hi all,
I have a theoretical question.
In what ways apparent qualitative and quantitative sex differences are or are not addressed by simply adjusting for sex in a multivariate model?
The thing is that I observed in different univariate models that 3 of my 6 variables (for the multivariate model) had quantitative or qualitative sex differents... then I adjusted for sex and age in the multivariate model, but I'd like to explain in which way those genetic sex differences in some of the variables are addressed or not in the multivariate model just by adjusting for sex. Does it make sense?

Dear all,
I have run without problems a multivariate IP model for 6 variables.
The thing is that now I would like to add another latent common A factor that loads only on 3 of the 6 variables to see if this "new" 2-IP factor model (two Ac factors) fits better the data than the 1-IP factor model (just one Ac factor for all the observed variables).
But I think I’m doing something wrong because the model doesn't understand that the second common A factor is loading only in the first 3 observed variables. Can anybody help me? Many many thanks!

Hi all,

I'm new to OpenMx and SEM, and I have just read through the various examples on twin modelling. Just wondering, if I have a moderator variable which varies within twin 1 and twin 2 and also across twin pairs, how do I go about specifying it as a definition variable? Or do I have to do bivariate analysis instead (treating the moderator variable as another variable?)

Thank you very much!

Cheers,
Yi