In Arabidopsis, flower development is controlled by sets of homeotic genes. How many classes of these genes are there, and what structures are formed by their individual and combined expression?

Key Concepts

Homeotic Genes

Homeotic genes are a group of regulatory genes that determine the identity of body parts during development. In plants like Arabidopsis, these genes play a crucial role in specifying the formation of floral organs. Mutations in homeotic genes can lead to the transformation of one organ type into another, illustrating their importance in developmental biology.

ABC Model of Flower Development

The ABC model describes how three classes of homeotic genes (A, B, and C) interact to control the development of floral organs in plants. Class A genes are responsible for sepal and petal formation, Class B genes for petal and stamen development, and Class C genes for stamen and carpel formation. The overlapping expression of these genes determines the identity of each floral organ.

Gene Expression Patterns

Gene expression patterns refer to the specific spatial and temporal activation of genes during development. In the context of flower development, the combined expression of homeotic genes leads to the formation of distinct floral structures, such as sepals, petals, stamens, and carpels. Understanding these patterns is essential for deciphering how complex structures arise from simple genetic instructions.