Behavioral Genetics Models

Help with thinking about a non-trivial GxE twin model
On a phenotypic level, I'm testing a model where Trait1 is moderating the effect of environment on Trait2.
However, when wanting to test my model within a genetic level, I'm having trouble to figure out what model I can use that will be most similar to the claim I have within the phenotypic level.
I can test whether my environmental factor moderates the genetic effects of Trait2 (with a GxE twin model). But this misses the part where Trait1 (which is highly heritable), moderates the association (or maybe the moderation?).

Longitudinal modeling with extended twin design
I have a couple of questions regarding my research and I would really appreciate getting some feedback if my undertaking is reasonable.
I am investigating stability of a political phenotype in a two-wave panel design. I'm including not only twins in my analysis, but also one non-twin full sibling. The scripts are standing and working (verified with replication).

GxE with ordinal manifest in RAM
I'm trying to build a Purcell style GxE model in RAM. I have not found any script for this so I created it from scratch. Right now I have a two ordinal manifests (twin 1, twin 2, same phenotype, 4 cats, 3threshs). The moderator will be continuous in the end. However, right now for experimental reasons I have created a binary moderator (sex) for me to easily check if my model does produce accurate results.
- Read more about GxE with ordinal manifest in RAM
- 7 comments
- Log in or register to post comments



ACE output: what is the p
I run the ACE model and got a summary table which reports the p among others.
The p is also not clear to me. Apparently it is higher for the winning model, but what exactly is this p?
Thanks,
Valentina
- Read more about ACE output: what is the p
- 1 comment
- Log in or register to post comments

ACE RAM model with ordinal manifest
I've been trying everything to get an ordinal manifest working in RAM models but I can't get it done. Also, didn't find anything online about this, as most examples have matrix specification. Would be very appreciated to get some help. Besides from the solution below, I have also tried every possible way with mxthreshold and umxthresholdmatrix.
- Read more about ACE RAM model with ordinal manifest
- 12 comments
- Log in or register to post comments

really similar AIC
I run the ACE model and submodels, and the AIC are really similar.
ACE 2579
AE 2577.5
CE 2577.3
E 2584
Overall, I always get a difference of 1 between the AIC.
The best winning model is always coherent with the results of the correlation analysis, so I tend to trust it, however, the difference is really little.
Is there a way to establish what is a significant difference between AIC?
Thank you all!
Valentina
- Read more about really similar AIC
- 7 comments
- Log in or register to post comments

ACE: negative variance component from H.Maes’ published script and slides
could you help provide some insights as to why running the following script, which uses data(twinData), gives negative estimates for Vc in an ACE model?
https://ibg.colorado.edu/cdrom2020/maes/twinModeling/oneACEvc.R
These are the most relevant lines related to the model:

Step 1: Testing basic assumptions (equal means & variances for twin 1/twin 2 and MZ/DZ pairs)
I am following the steps laid out in [this](https://vipbg.vcu.edu/media/course/HGEN619_2015/TwinModels.pdf ) openmx presentation and could use help with step 1.
1. Use data to test basic assumptions (equal means & variances for twin 1/twin 2 and MZ/DZ pairs)
Pagination
- Previous page
- Page 6
- Next page