Context

Theoretical Introduction

The Pedigree, or family tree, is a graphical representation that helps biologists visualize the genetic relationships among an extended family. Similar to a genealogical map, a pedigree illustrates family relationships and shows which members of a family are affected by a genetic condition. This tool is indispensable in human genetics as it allows the identification of genetic inheritance patterns and predicts the risk of an individual acquiring a specific genetic trait or disease.

Genetic traits or diseases can be dominant or recessive. Dominant traits are those that manifest in the phenotype even in a single dose (heterozygosity), while recessive traits only manifest in a double dose (homozygosity). This information about dominance and recessiveness is fundamental in the interpretation of pedigrees.

The study of pedigrees involves the analysis of inheritance patterns, which can be varied: Autosomal Dominant, Autosomal Recessive, X-Linked Dominant, and X-Linked Recessive. Each of these patterns presents specific characteristics that aid in the identification and prediction of genetic transmission risks for future generations.

Context

In the real world, the construction and analysis of pedigrees have very relevant applications, especially in the medical field. Through pedigrees, it is possible to identify individuals carrying genes for hereditary diseases, which helps in the prevention and treatment of these conditions. In addition, pedigrees are used to unravel the genetic history of a family, assisting in genetic counseling for future parents.

The evaluation of pedigrees is also an essential tool in genomic research. It allows scientists to identify which genes are linked to which conditions, leading to a better understanding of human biology and, thus, to more effective treatments for a variety of diseases.

Practical Activity

Activity Title: Unraveling Genetic Stories: The Construction and Analysis of Pedigrees

Project Objective:

The project's objective is to provide students with the opportunity to apply, in a practical example, the techniques of developing and analyzing pedigrees, enhancing their teamwork, time management, research, scientific analysis, and scientific writing skills.

Detailed Project Description:

The student groups (3 to 5 members in each group) will develop two pedigrees: one based on a real case study of a genetic disease, and the other based on a fictional scenario created by the group. Students will use the pedigrees to analyze genetic inheritance patterns, make predictions about the probability of future generations being affected by the genetic condition, and discuss the implications of their results.

It is expected that each student invest five to ten hours of work in the project, which must be completed and delivered within one month.

Required Materials:

• Biology books or online materials on genetics and pedigrees.
• Paper and pen to draw the pedigree.
• Computer for research and report writing.

Step-by-Step for Activity Execution:

1. Research and selection of the case study: All group members should research genetic diseases, and then, as a team, decide on a disease for the first pedigree. The selected disease should have sufficient information available to allow the analysis of genetic inheritance patterns.

2. Development of the case study pedigree: Students should research and collect as much information as possible about the family affected by the selected disease, and then use this information to build the pedigree.

3. Analysis of the case study pedigree: The group should analyze the pedigree to determine the genetic inheritance pattern and calculate the probabilities of future generations being affected by the disease.

4. Creation of a fictional pedigree: Students should create a fictional scenario, with a new imaginary genetic disease, and develop a pedigree from it. The scenario should be realistic and consistent with genetic principles.

5. Analysis of the fictional pedigree: Just like in the case study pedigree, students should analyze the genetic inheritance pattern and calculate the probability of future generations being affected by the disease.

6. Report writing: After completing the practical activity, each group should prepare a detailed project report addressing the Introduction (with the project's context and objectives), Development (where they explain the theory of pedigrees, describe in detail the activity's execution, present the results obtained, and discuss the analyses performed), Conclusion (where they summarize the main points of the project, comment on the lessons learned, and conclude on the activity), and finally, the Bibliography used.

Project Deliverables:

Groups must submit a written report, in digital file format, in addition to the pedigrees developed during the project. The report should include the following sections: Introduction, Development, Conclusions, and Bibliography, following the guidelines described in the step-by-step. The pedigrees should be included in the Development section and must be clearly legible.

The report writing should be done collectively, promoting discussions and idea exchanges among group members. This activity will not only assess students' knowledge of the topic but also their collaboration, communication, problem-solving, and time management skills.