Complex sentence: Apetala 2 (AP2) is a gene coding for a member of a large family of plant-specific transcription factors, the AP2/EREBP family, from "Arabidopsis thaliana" which plays a role in the ABC model of flower development.
Split into simpler sentences: Apetala 2 (AP2) is a gene coding for a member of a large family of transcription factors, the AP2/EREBP family. In "Arabidopsis thaliana" which plays a role in the ABC model of flower development.