• Many times as biology teachers we  teach biological concepts as isolated units without making  connections with the real world.  Learning  as a whole is more meaningful and enjoyable when content and process are learned within the context of a real problem, and when they have an impact on a real audience. The purpose of this exercise is to explore articles on genetic diseases and to utilize various writing techniques to improve literacy in the biology classroom.  Examples of writing techniques utilized in this module include point of view, comparative and reflective writing.  Genetic diseases are common in many ethnic populations, therefore articles of this nature are potentially excellent sources of study for a variety of audiences.  By having students read, write and reflect on these articles, this approach will promote both literacy and critical thinking skills.  Critical thinking skills learned in the science classroom from these activities will impact students in many ways and help them  make choices about issues they will confront in their daily lives.

To foster science literacy.
To develop critical thinking skills.
To improve communication skills.
To enable students to make real world connections.
 
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• Biology students
• Grades:  9-12

Notes to the Teacher: to top 

These series of  reading, writing, and speaking  activities  may serve as a culminating  project or as review in preparation for an examination. Students need to have a working knowledge of  the  terms associated with  the following  topics: human genetics, evolution, human reproduction and development.  Students need to be aware of  current trends and methods utilized in scientific  research.  The first time the teacher tries these activities, I recommend that the teacher choose a short article no longer than 2 typed pages.  The article should contain specific information on a disease that is relevant to her class' community.   On the whole, genetic diseases are interesting and exciting for  students to read about and they provide  excellent sources of information  to captivate students.  Information in the article chosen by the teacher should include the following details: the name of disease, the population it affects, the chromosome it is located on, the symptoms, the diagnosis, current techniques used in studying this gene, current therapies and problems with coping with this disease.  It is necessary  for the teacher to go over each activity step by step with the student.   When the student is experienced and feels confident in approaching other articles on his/her own, the teacher should allow the student to proceed. The teacher should allow time for sharing student samples.

1. Required of students: Students need to have a working knowledge of  the  terms associated with  the following  topics: human genetics, evolution, human reproduction, and development
2. Class time needed: 90 min. or 2 class periods
3. [Hazards / Precautions]: NA

[Prior Knowledge or Vocabulary Necessary to Complete Activity]

Several thousand genetic disorders are known to be inherited as recessive traits.  These disorders range from non-lethal defects like albinism to deadly diseases like cystic fibrosis. In the case of recessive disorders, the heterozygous individuals are normal in phenotype since they contain only one copy of the deleterious gene. The homozygous individual on the other hand contains both copies of the deleterious recessive genes and this poses serious threats to the individual. Some common recessive disorders include cystic fibrosis, Tay-Sachs and sickle cell anemia.  These three diseases provide excellent insights in the study of genetic diseases and is a good focus for improving literacy in the high school classroom.

Cystic fibrosis, the most common lethal genetic disease in Caucasians, is characterized by a decreased permeability in sweat gland duct and airway epithelia.   In sweat duct epithelium, a decreased Cl- permeability accounts for the abnormally increased salt content of sweat.  It is this loss of chloride function in the airways which lead to poor fluid secretion, mucous accumulation and resultant bacterial infections. The cystic fibrosis gene was cloned in 1989 and current studies are being conducted to understand  its regulation.   

Tay-Sachs  is a disease common among Jews .  It is caused by a dysfunctional enzyme that fails to break down a class of brain lipids. Tay-Sachs causes rapid degeneration of the central nervous system and leads to death in early childhood sufferers. 

Sickle cell anemia affects one out of 400 African Americans. This disease is caused by a substitution of a single amino acid in the hemoglobin protein resulting in sickle shaped red blood cells.  These sickle-shaped red blood cells lodge in small passageways of the circulatory system when oxygen levels are low and leads to sickle cell crisis.
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1. Purpose: To improve writing across the curriculum
2. Equipment: Journal Articles on  genetic diseases associated  with  specific ethnic groups

Step 1
Prewriting Activity:

Read the article once, underline important terms, make notes and place question marks  in the margin in response to  ideas, terms and sentences which are not clear.

Step 2
Analysis and Note Taking Strategies

Reread the article and do a triple entry.  A triple entry is a note taking strategy where the student divides his page into three columns and makes a table.  In the first column the student outlines the basic facts presented by the author.  In the second column the student paraphrases what he thinks the author is saying.  In the third column the student writes questions or reactions that come to mind.

Guided questions to promote understanding.

1. What is the disease?
2. How is the disease transmitted?
3. What are the symptoms?
4. How is the disease diagnosed?
5. How is the disease treated ?
6. How  is this  disease studied?
7. Has the gene which causes this disease been identified?  Has it been mapped?
8. What is the cascade of events on the molecular level which accounts for this disease?
9. What is the cascade of events on the cellular level which accounts for this disease?
10. Which ethnic group contains copies of  this gene?
11. What is the evolutionary history of this gene?

Step 3
Point of View Writing:  For example:  The student takes the point of view of the gene which causes the mutation for sickle cell and writes a passage describing his journey within that population.
 
Step 4
Oral Presentation: Prepare an oral presentation on the  disease.

Step 5
Public Service Announcement: A brief outline of the disease designed to  promote public awareness.

Home work Assignment: Complete steps 1-5 with another article
Try the above writing strategies using  another article recommended by the teacher  which focuses on another  disease not common within your ethnic group.

Step 6 Comparative Analysis:
Compare and contrast the first disease with the second disease and create a dialogue between the  two diseases.

Reflection & Concluding Activity:  Write an essay about how  this activity helped to improve your understanding of other ethnic groups.  Students should share writing samples with the class.
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Evaluate triple entry for important points outlined in the article. Check the answers to guided questions.  Evaluate point of view writing, oral presentation, public service announcement, comparative analysis and reflective writing  for creativity, comprehension,  and clarity.

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1.  Formal Research Papers on  Genetic Diseases
2.  High School Symposium on Genetic Diseases
3.  Expert panel discussing  genetic diseases at an International Conference (Simulation)
4.  Learning logs, journal entries on Genetic Diseases
5.  Portfolio on other kinds of Genetic Diseases (sex-linked, autosomal dominant)
6.  Interview with doctors, patients, foundations etc.
7.  Internship at a research lab
8.  Volunteer at a hospital
9.  Design a web page for a Foundation which supports a genetic disease
10. Write a proposal requesting funds to study a genetic disease
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Articles

Curse and blessing of the ghetto. (concentration of  Tay-Sachs disease in Eastern European Jews helps us learn how genetic diseases (evolve) Jared Diamond Discover March 1991 v 12n3 p60(6)
A pox upon our genes; smallpox vanished twelve years ago, but its genetic legacy may still linger within us. Jared Diamond. Natural History 1990 v n2 p26 (3)
Sweet death. (genetic basis of diabetes) Jared Diamond. Natural History Feb 1992 n2 p2(4)
Blood Genes, &  Malaria.  Jared Diamond. Natural History 1989 v n2 p8(6)

Websites

http://www.cfff.org/newindex.thm
http://www.csuchico.edu/bio/personell/bell/cys.htm/
http://nce.nserc.ca/books/cf3eng.htm
http://advelearn.Irdc.pitt.edu/belvedere/materials/Evolution/sickle.htm
http://www.sasked.gor.sklca/docs/midlsci/sci/msc.html
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