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Behavioral Genetics Models

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

Saturated vs ACE model- different correlations

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Behavioral Genetics Models
Hi all,

I am trying to fit a univariate model.

I fitted the saturated model first and I got correlations of 0.64 and 0.34 for MZ and DZ respectively.

However, when I fitted the ACE model, I got these results:
A=0.04
C=0.52
E=0.44

So, I decided to check the correlations from the ACE model and I got 0.56 and 0.54 for MZ and DZ respectively.
I know that correlations may change from the ACE to the saturated model. However, these differences are huge.

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No user picture. diana Joined: 04/17/2019

what are the meanings of definition variables in SEM in twin studies

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Behavioral Genetics Models
In the structural equation model, the definition variables are usually added in the regression of thresholds, such as age and sex. But I don't thoroughly figure out the meanings of them.

For instance, I want to estimate the heritability of smoking( binary variable) and age is added to adjust the threshold.

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No user picture. thughe01 Joined: 10/18/2009

ACE model with technical replicates

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Behavioral Genetics Models
I'm re-entering the world of SEM after a hiatus and slowly familiarising myself with OpenMx (previous Mx user). I've successfully implemented some simple uni- and bi-variate VC models for some of our latest twin data (microbiome phenotypes) using the umx packages.

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No user picture. noamm Joined: 10/10/2018

Failure to obtain CI's for a umx model

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Behavioral Genetics Models
Hi all,

I have used umx for a bivariate sex-limitation model, using the umxSexLim function, which have been a great help. However, I've failed in trying to compute CI's for my estimates, or any other indication of significance. Attached below are all the options I've tried. I would appreciate any help in how to compute any indication of significance.

Thanks!

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

Modeling Suggestions for Experimental Data

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Behavioral Genetics Models
Question for the group: How might one go about modeling experimental data with twin respondents?

I ran a single-factor survey experiment with a small group of twin respondents (MZs and DZs, mainly same sex). There were two conditions. I randomly assigned twins to receive either:

Conditions A A
Conditions B B
Or
Conditions A B (or B A)

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

Age as covariate or moderator

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Behavioral Genetics Models
I looked around the forum, and found referrals to a post that might address this issue, but that page wouldn't load anymore, so I thought I'll post my question here.

I'm running a set of univariate ACE models, on a range of outcomes. I have two age groups (3-4 and 7-8), that I would like to analyse separately, by also combined.

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No user picture. camus Joined: 03/21/2019

Obtain 95%CI for ACE model- script revised from Dorothy Bishop

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Behavioral Genetics Models
Hi, I am new with R and OpenMx. Recently I revised Dorothy Bishop's script to run ACE models. However, her original code could not get the 95%CI for of A,C,E estimates, but only 95%CI for Unsquared path estimates. I know mxCI() can obtain 95%CI, but after various attempts, it never works for me. Could any expert have a look of the code and let me know how should I add it?
Thanks!
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No user picture. diana Joined: 04/17/2019

I am wondering if define variables will decrease E and increase A?

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Behavioral Genetics Models
I am wondering if too many define variables will decrease E and increase A?

For instance, I want to estimate the heritability of coronary heart disease (CHD), should I adjust all the risk factors of CHD as much as possible, such as smoking, drinking and BMI? I'm afraid that it will overestimate A and underestimate E since I saw a revelent [paper](https://www.ncbi.nlm.nih.gov/pubmed/15520515/).

Many thanks!

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No user picture. Qiuzhi Xie Joined: 12/27/2018

About the overlap on the genetic and shared environmental factors

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Behavioral Genetics Models
I am conducting the Cholesky model and wondering how to judge if two phenotypes significantly overlap on a genetic or environmental factor. It should be judged by the loading factor and the 95% CI, right? In the following example, only the third phenotype (P3) does not significantly overlap with the others on the A1 (genetic) factor, as the lower boundary of the 95% CI is smaller than .00. Am I right?

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No user picture. diana Joined: 04/17/2019

GxE model for binary variable

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Behavioral Genetics Models
Hello! I am trying to fit a GxE model. The phenotype is a binary variable, and the moderator is measured on a 6-point scale .

I want to use the code posted in [there](http://ibg.colorado.edu/cdrom2016/franic/Moderation/Practical/DO_NOT_OPEN_Moderating_covariances_practical_solved.R), but this code is suit for continuous variable and I don't know how to change it to be suit for binary variable. Could you tell me what lines I should change or add?

Because I'm pressed for time, I am sorry to directly ask for solution instead of learning by myself.

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