The organelle that contains genetic information in both plant and animal cells is the nucleus.

Here's why:

* DNA Location: The nucleus houses the cell's DNA, which contains the instructions for building and maintaining the organism.

* Chromosomes: DNA is organized into structures called chromosomes within the nucleus.

* Gene Expression: The nucleus controls the expression of genes, which determines the traits and functions of a cell.

While other organelles like mitochondria and chloroplasts (in plants) have their own DNA, the nucleus is the primary repository of genetic information for the entire cell.