Question

List the main classes of zygotic genes. What is the function of each class of these genes?

Short answer

Question: List the main classes of zygotic genes and describe their function. Answer: The three main classes of zygotic genes are maternal effect genes, segmentation genes, and homeotic genes. Maternal effect genes are important for establishing the body axes during early development and controlling the localization of cellular structures. Segmentation genes are responsible for the formation and positioning of body segments, dividing the embryo into distinct parts along the anterior-posterior axis. Homeotic genes determine the identity and development of body segments, organs, and tissues, helping maintain the proper organization of the body plan.

Step-by-step solution

Define Zygotic Genes

Zygotic genes, also known as zygotic-effect genes, are genes that are activated in the zygote, which is the first diploid cell formed by the fusion of two haploid gametes during fertilization. These genes are important for the regulation of early development and cellular processes in multicellular organisms such as animals and plants.

List the Main Classes of Zygotic Genes

There are three main classes of zygotic genes: 1. Maternal effect genes 2. Segmentation genes 3. Homeotic genes

Function of Maternal Effect Genes

Maternal effect genes are a specialized class of zygotic genes derived from the mother. These genes are important during the early development of the embryo, as they help in establishing the anterior-posterior (head-tail) and dorsal-ventral (back-belly) axes. In some organisms, these genes play a crucial role in controlling the initial localization of cellular structures and organelles to ensure proper embryonic patterning and development.

Function of Segmentation Genes

Segmentation genes are responsible for the formation and positioning of body segments in the developing organism. These genes are essential in controlling the organization of cells along the anterior-posterior axis, dividing the embryo into distinct segments. They establish the basic body plan and help create a blueprint for the future development of the organism. Segmentation genes can be further divided into three sub-groups: 1. Gap genes: Define the broad regions along the anterior-posterior axis. 2. Pair-rule genes: Regulate the development of alternating segments. 3. Segment polarity genes: Determine the anterior-posterior organization within each segment.

Function of Homeotic Genes

Homeotic genes are a group of zygotic genes that determine the identity and development of body segments, organs, and tissues in multicellular organisms. These genes control the unique development of each body part and help maintain the proper organization of the body plan. Homeotic genes encode transcription factors, which are proteins that bind to specific DNA sequences and regulate the activity of other genes. The most well-known homeotic genes are the Hox genes, which play a crucial role in determining the overall body plan in animals.