Correct option is B
The AP2 (APETALA2) gene is a floral homeotic gene transcribed in all four whorls during flower development. It plays a broad role in determining floral organ identity and development. AP2 is not restricted to specific whorls and is involved in regulating genes that control floral meristem development, making it unique among the options provided. Other genes like AP1, AP3/PI, and AG are expressed in specific whorls and are part of the ABC model of floral development.
Information Booster:
- AP2 regulates floral meristem identity and organ specification across all whorls.
- AP1 is mainly expressed in sepals and petals.
- AP3/PI (APETALA3 and PISTILLATA) control petal and stamen development.
- AG (AGAMOUS) is involved in specifying the reproductive organs, stamens, and carpels.
5. The ABC model explains how combinations of genes specify floral organ identity. AP2 is unique among the floral homeotic genes because of its expression in all four whorls.
6.The ABC model defines the roles of homeotic genes in floral organ specification.
7.AP1, AP3/PI, and AG are expressed in specific whorls, unlike AP2.
Additional Knowledge:
- AP1: This gene specifies sepal and petal identity and is active early in floral development. It is not expressed in the reproductive whorls.
- AP2 (Correct Answer): AP2 is a member of the AP2/EREBP transcription factor family. It regulates floral organ development across all whorls, including sepals, petals, stamens, and carpels. Unlike AP1, AP3/PI, and AG, it is broadly transcribed.
- AP3/PI: These genes are expressed in petals and stamens. They work as part of the B-function genes in the ABC model of floral organ identity.
AG: AGAMOUS is a C-function gene expressed only in the inner two whorls, where it specifies stamen and carpel identity.
