ACEt (version 1.3)

AtCtEt: The ACE(t) model

Description

The ACE(t) model with the A, C and E variance components as functions with respect to age modelled by B-splines.

Usage

AtCtEt(data_m, data_d, model = c('d','d','d'), knot_a = 5, knot_c = 5, knot_e = 5)

Arguments

data_m

An $N_m$ x 3 data matrix for MZ twins. $N_m$ is the number of MZ twin pairs. The first two columns are traits and the third column is age (or other covariates).

data_d

An $N_d$ x 3 data matrix for DZ twins. $N_d$ is the number of DZ twin pairs. The first two columns are traits and the third column is age (or other covariates).

model

A character vector of length 3. Each element specifies the function for the A, C or E component respectively. The A and C components can be 'd'(dynamic), 'c'(constant) or 'n'(NA). The E component can only be 'd' or 'c'. Thus, $model=c('c','c','c')$ is cor

knot_a

The number of interior knots of the B-spline for the A component, which must be no less than 3. The default value is 5.

knot_c

The number of interior knots of the B-spline for the C component, which must be no less than 3. The default value is 5.

knot_e

The number of interior knots of the B-spline for the E component, which must be no less than 3. The default value is 5.

Value

• n_beta_a
  The number of spline coefficients for the A component.
• n_beta_c
  The number of spline coefficients for the C component.
• n_beta_e
  The number of spline coefficients for the E component.
• beta_a
  The estimated spline coefficients of the A component.
• beta_c
  The estimated spline coefficients of the C component.
• beta_e
  The estimated spline coefficients of the E component.
• hessian
  The approximated Hessian matrix from the minus log-likelihood.
• con
  The indicator of convergence of the optimization algorithm.
• lik
  The minus log-likelihood.
• knots_a
  A vector of the knot positions for the A component.
• knots_c
  A vector of the knot positions for the C component.
• knots_e
  A vector of the knot positions for the E component.

References

Liang He, Mikko J. Sillanp��, Karri Silventoinen, Jaakko Kaprio, Janne Pitk�niemi, Estimating modifying effect of age on genetic and environmental variance components in twin models. Genetics, 2016

Examples

data(data_ace)

result <- AtCtEt(data_ace$mz, data_ace$dz, model=c('d','d','c'))