Judith Averbeck, SND
Notre Dame Academy
Type of Entry
Type of Activity
What question does this activity help students answer?
This demonstration is a dramatic way to help students conceptualize the length of a real human gene and the relative lengths of its introns and exons.
Notes for the teacher:
The actual base sequence of the human adenosine deaminase gene must be downloaded from the source disk provided and printed out. If fanfold paper is used, the entire gene is in "one piece" and can be stretched across the room for effect. The advantage to using the disk instead of downloading from the internet database (Genbank, for example) is that the exons are indicated within the base sequence and the mRNA is also given.
Required of students:
Students need only to examine the printout and make observations.
It takes about 20 minutes to print out the entire gene on a dot-matrix printer.
Class time needed:
Students typically take 5-10 minutes to examine the printout. Other activities are at the discretion of the teacher.
The entire DNA base sequence of the human adenosine deaminase gene is printed out from the source disk provided. The enormous length of a single gene as well as the immense difference in length between intron and exon segments are demonstrated in a way that students will not easily forget.
Source disk from which to download gene sequence, computer and printer.
The DNA base sequence of the human adenosine deaminase gene is printed out from the source disk provided. The exons are underlined in the text, but the teacher may want to highlight them for improved visibility. If fanfold paper is used, the entire gene is "in one piece" and can be dramatically draped across the classroom.
The enormous length of a single gene is demonstrated, as well as the immense difference in length between intron and exon segments. The messenger RNA sequence is also provided on the disk, and can be used to illustrate various relationships -- for example, that only exons are transcribed.
Method of evaluation/assessment:
This activity is mainly an attention-getter and/or reinforcer. Assessment, if any, would probably be in the form of a test question relating to size of genes.
The notes relating to research on mutant forms of the ADA gene (found on the source disk following the base sequence) can be used to discuss neutral and detrimental mutations.