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The C. elegans embryo is a powerful model system for studying the mechanics of metazoan cell division. Its primary advantage is that the architecture of the syncytial gonad makes it possible to use RNAi to generate oocytes whose cytoplasm is reproducibly (typically >95%) depleted of targeted essential gene products via a process that does not depend exclusively on intrinsic protein turnover. The depleted oocytes can then be analyzed as they attempt their first mitotic division following fertilization. Here we outline the characteristics that contribute to the usefulness of the C. elegans embryo for cell division studies. We provide a timeline for the first embryonic mitosis and highlight some of its key features. We also summarize some of the recent discoveries made using this system, particularly in the areas of nuclear envelope assembly/ dissassembly, centrosome dynamics, formation of the mitotic spindle, kinetochore assembly, chromosome segregation, and cytokinesis.
1. The C. elegans embryo as a system to study cell division
The C. elegans embryo is a powerful model system for studying the mechanics of metazoan cell division. Its primary advantage is that the syncytial gonad makes it possible to use RNA interference (RNAi) to generate oocytes whose cytoplasm is reproducibly (>95%) depleted of targeted essential gene products. Introduction of dsRNA rapidly catalyzes the destruction of the corresponding mRNA in many different systems. However, depletion of pre-existing protein is generally a slow process that depends on the half-life of the targeted protein. In contrast, in the C. elegans gonad, the protein present when the dsRNA is introduced is depleted by the continual packaging of maternal cytoplasm into oocytes (Figure 1). Since depletion relies on the rate of embryo production instead of protein half-life, the kinetics tend to be similar for different targets. By 36-48 hours after introduction of the dsRNA, newly formed oocytes are typically >95% depleted of the target protein.
Explanation:
Answer:
The phylogenetic graph uses several types of variables to be formed, while other models use only one type of variable.
Explanation:
To create a phylogenetic chart, matrices with data on the studied species are used. These data are composed of morphological, chemical and / or genetic information that allow a detailed investigation about the ancestry of each species, in addition to allowing the correct grouping based on this ancestry and evolution.
A phylogenetic graph is different from other molecular models due to the number of data considered by it, since other models, such as the molecular clock, for example, only consider genetic based information.
A Light Year is a mesurement of 5.879e+12 miles Compressed into one unit of mesurement or a "Light Year"
Light Years are used in the measurement of the universe because, to put it simply, SPACE IS BIG! The use of Light Years (5.879e+12 miles) Breaks the observable universe down into manageable chunks for astrologists.
