Teacher's Notes

NSES

The national standards that will be addressed in this lesson are those that relate to the molecular basis of heredity and personal and community health.  Molecular biology is a major frontier of science and students should have a basic understanding of the processes of inheritance to be aware of the many implications involved in gene transmission.  The scientific community is continually developing new treatments for diseases, and it is up to the citizens to take an informed position on some of the practical and ethical implication of humankind’s capacity to manipulate living organisms.

The symptoms and manifestation of diseases, whether curable or not, can be dependent on many factors, such as human resistance, the virulence of the disease-producing organism, or the environmental factors effect the individual. Many diseases can be prevented, controlled, or cured. Some diseases, such as cancer, result from specific body dysfunctions and cannot be transmitted. Many of these types of conditions have been found to run in families, and thus sparked much research for genetic research.

DESE

The state standards that will be addressed are those relating to inheritance.  The genetic code dictates the genotypic and phenotypic characteristics of an individual.  These characteristics are a combination of the characteristics of one’s parents.  The transmission of genetic information can be predicted using the principles of Mendelian genetics.

The Concept: 

This lesson will build upon students’ previous knowledge of DNA, genes, chromosomes, the chemicals that make up DNA.  Students will identify Heredity by using DNA evaluation and relate this to the genes transmitted within their family.  This concept will be the underlying scientific concept further investigated in lesson 4.  

Exploration activities:

In groups, student will brainstorm diseases that they have heard about.  Then, teacher directed discussion will begin and a chart will be completed dealing with the acquisition of conditions.  The chart will attempt to determine if the specified conditions are genetically transmitted or a factor of the environment.    Students will be reminded that even with DNA information lending towards illness, some things can be done to prevent or lessen the severity of symptoms. 

Description of Data

The students will identify conditions they know about, and hopefully they will hit upon a few of the ones identified in the teacher chart.  They will complete the chart below in their small groups and fill in any further implications when it is reviewed as a class.  

Concept Introduction:

The students will be instructed to view "What is heredity?" and "What is a trait?" on  Tour of the Basics.  Students will take notes on the main concepts:  What is heredity, how do we inherit our traits, what is a trait, etc.  The students will also be directed to review the brief explanation of the process of DNA fingerprinting at the following website:  http://www.pbs.org/wgbh/nova/sheppard/labwave.html  We will then review this information as a class to ensure everybody has all the pertinent information.

Application:

We will again extract DNA from our cheek cells, but in addition, obtain cheek cell samples from relatives (parents, grandparents, siblings, or cousins) to see how much DNA we share.  We will review the process of obtaining cheek cells in class by the students obtaining their own, then they will be required to perform this process independently at home with their family members.  We will then extract the DNA from all our samples and prepare it for DNA fingerprinting.  This exercise will take several class periods, but it will provide a basis for the procedures in the next lesson.  

Protocol - DNA extraction form cheek cells

History:  

For students to get an understanding of the history of this scientific concept, they will review the timeline from the 1970’s through the 1980’s found at www.dnai.org focusing on:

Frederick Sanger (1918-) Sanger started working for A. C. Chibnall, on identifying the free amino groups in insulin. In the course of identifying the amino groups, Sanger figured out ways to order the amino acids. He was the first person to obtain a protein sequence. By doing so, Sanger proved that proteins were ordered molecules and by analogy, the genes and DNA that make these proteins should have an order or sequence as well.

Kary Mullis(1944- ) invented the polymerase chain reaction (PCR), a technique that amplifies specific DNA sequences from very small amounts of genetic material. Unlike most scientific discoveries, the invention of PCR was not the product of years of painstaking labor, but came to Mullis in a flash of inspiration while driving.  

Alec Jefferys - developed DNA fingerprinting/profiling

Related Websites:  

http://www.dnai.org

http://gslc.genetics.utah.edu/units/basics/tour/

http://www.pbs.org/wgbh/nova/sheppard/labwave.html 

References:  

http://www.riverdeep.net/

http://gslc.genetics.utah.edu/units/basics/tour/

http://encarta.msn.com/encyclopedia_761579857/DNA_Fingerprinting.html

Curtis, H. & Barnes, N. S., Biology of Cells, Worth Publishers, Inc., 1989.