Xenopus laevis

Definition

Xenopus laevis, commonly known as the African clawed frog, is a species widely used in developmental biology research due to its easily observable embryonic development and external fertilization. This amphibian is particularly important for studying processes like body axis establishment, gene expression transitions from maternal to zygotic control, and early embryonic stages including cleavage and blastulation.

5 Must Know Facts For Your Next Test

1. Xenopus laevis eggs are large and transparent, making them ideal for visualizing early developmental stages under a microscope.
2. This species undergoes distinct cleavage patterns, including radial cleavage, which contributes to the regular arrangement of blastomeres during early development.
3. The establishment of body axes in Xenopus laevis begins with the fertilized egg's orientation and is influenced by factors like cortical rotation and the distribution of maternal determinants.
4. During the maternal-to-zygotic transition, transcription begins to shift from maternal mRNA control to zygotic gene expression, a crucial point for proper development in Xenopus laevis.
5. Xenopus laevis has been instrumental in various biological studies, including those related to stem cells, organ development, and responses to environmental changes.

Review Questions

• How does the cleavage pattern in Xenopus laevis influence the subsequent stages of development?
  • The cleavage pattern in Xenopus laevis is characterized by radial cleavage, which results in symmetrical cell division and organization of the blastomeres. This regular arrangement is essential for forming a well-structured blastula and sets the stage for later developmental processes such as gastrulation. The specific arrangement of cells also influences fate determination and axis formation, making it critical for proper embryonic development.
• Discuss the role of maternal factors in establishing body axes in Xenopus laevis during early development.
  • Maternal factors play a significant role in establishing body axes in Xenopus laevis through mechanisms like the localization of mRNA and proteins within the oocyte. After fertilization, these factors guide cortical rotation, which helps position key determinants that signal for anterior-posterior and dorsal-ventral axis formation. This maternal influence is crucial as it lays the groundwork for future zygotic gene expression and overall body plan.
• Evaluate the significance of using Xenopus laevis as a model organism in developmental biology research, particularly regarding gene expression transitions.
  • Using Xenopus laevis as a model organism is highly significant in developmental biology due to its unique characteristics that facilitate the study of complex processes such as gene expression transitions. Its large embryos allow researchers to manipulate genes and observe outcomes during critical stages like the maternal-to-zygotic transition. This transition is pivotal because it marks a shift from reliance on maternal mRNA to zygotic transcription, revealing insights into gene regulatory networks that govern development and how disruptions can lead to developmental anomalies.

Related terms

Embryogenesis: The process of development of an embryo from the fertilization of the egg to the formation of distinct organ systems.

Cleavage: The series of rapid mitotic divisions that occur after fertilization, leading to the formation of a multicellular structure from the zygote.

Blastula: An early stage of embryonic development characterized by a hollow sphere of cells that forms after cleavage.