Iowa Code § 633.273: Antilapse statute.

1. If a devisee dies before the testator, leaving issue who survive the testator, the devisee’s issue who survive the testator shall inherit the property devised to the devisee per stirpes, unless from the terms of the will, the intent is clear and explicit to the contrary.

2. A person who would have been a devisee under a class gift, if the person had survived the testator, is treated as a devisee for purposes of this section, provided the person’s death occurred after the execution of the will, unless from the terms of the will, the intent is clear and explicit to the contrary.