  For a finite graph $\Gamma$, let $G(\Gamma)$ be the right-angled Artin group
defined by the complement graph of $\Gamma$. We show that, for any linear
forest $\Lambda$ and any finite graph $\Gamma$, $G(\Lambda)$ can be embedded
into $G(\Gamma)$ if and only if $\Lambda$ can be realised as a full subgraph of
$\Gamma$. We also prove that if we drop the assumption that $\Lambda$ is a
linear forest, then the above assertion does not hold, namely, for any finite
graph $\Lambda$, which is not a linear forest, there exists a finite graph
$\Gamma$ such that $G(\Lambda)$ can be embedded into $G(\Gamma)$, though
$\Lambda$ cannot be embedded into $\Gamma$ as a full subgraph.
