Assignment

Human embryonic stem cells are pluripotent cell lines derived from the inner cell mass of human blastocyst-stage embryos. They have virtually an unlimited capacity to self-renew in the lab and can form into just about every cell type. Stem cells are very useful tools to study how developmentally regulated genes are expressed. They can be used to study the effects of mutations on developmental events and the processes of cell commitment, differentiation, and adult cell reprogramming. We can also compare human stem cell differentiation with other animal models. Molecular tools are allowing researchers to generate massive amounts of data regarding developmentally regulated genes. While this is great, one downfall is that it can be difficult and time consuming to access specific data sets. You may have noticed how many research articles appear when you do a literature search, and that it can sometimes be difficult to find exactly what you are looking for. Many databases have been created to aid researchers in finding pertinent research to help them with scientific investigations. One such database developed to aid developmental biologists is Life Maps. In this activity we will:

• Visit Life Maps
• Learn about mammalian development
• Research the development of a human organ/tissue on the Organ/Tissue Ontology Tre.

Participation in this activity will help you master module outcomes:

• Describe how different mammals accomplish developing into an organism that has the ability to produce viable offspring.
• Explain how genetic and environmental factors influence the development of mammals.
• Explain ethical dilemmas involved in utilizing mammals as developmental models.

There are three components to this activity.

• First you will read about mammal development and answer a set of questions (you are not required to turn these in).
• Second, you will explore the Organ/Tissue Ontology Tree (Links to an external site.)Links to an external site.
• Third, you will summarize our current understanding of human organ or tissue development and explain possible therapeutics for diseases of the structure.

You are not required to turn in your answers to the mammalian development questions, but you are encouraged to be comfortable with the information because you may see this material on an upcoming quiz.

After completion of this assignment you will turn in a one page summary of your current understanding of a human organ or tissue development.

Let's get started by visiting LifeG Maps.

After you read the material on mammalian development, there are ten questions for you to answer.

1. What is developmental path?

o Does a cell's specific temporospatial localization within an organ or tissue always dictate its functional fate?

2. What is a cell class?
3. What is holoblastic cleavage?
4. What is meroblastic cleavage?
5. What is the first event of gastrulation?
6. Describe the Wnt Pathway.
7. Describe the SHH Pathway.
8. Describe the Notch Pathway.
9. Describe the BMB Pathway.
10. Describe the FGF Pathway.

Now visit the Organ/Tissue Tree. Chose an organ or tissue and explore in the tree. Summarize the research that has been conducted and what the therapeutic applications of the research are. Your summary should include:

• Which lineages does this structure arise from?
• What is the anatomical structure and functions?
• How many genes are expressed in the development of the structure?
• How many High Throughput Gene Expression Comparisons and Large Scale Dataset Samples have been collected on this structure?
• How many cells comprise the organ/tissue and/or its related developmental paths?
• What is one of the therapeutic procedures tested in animal models or humans?

o What animal models were used for this treatment?
o Is this therapy in clinical trials or approved for use?

• Your summary submission should be a well-organized one page essay that explains, describes, analyzes and examines current understanding of the development of a human organ or tissue.