Dragon Genetics – Understanding Inheritance

In the simulation activity, Dragon Genetics – Understanding Inheritance, students mimic the processes of meiosis and fertilization to investigate the inheritance of multiple genes and then use their understanding of concepts such as dominant/recessive alleles, incomplete dominance, sex-linked inheritance, and epistasis to interpret the results of the simulation. This activity can be used as a culminating activity after you have introduced classical genetics, and it can serve as formative assessment to identify any areas of confusion that require additional clarification.

Download Student Handout: PDF format or Word format

Download Teacher Preparation Notes: PDF format or Word format

We invite comments on this Hands-On Activity and the accompanying Teacher Preparation Notes, including suggestions for other teachers who are planning to use the activity, useful preparatory or follow-up activities, additional resources or any questions you have related to the activity, or a brief description of any problem you might have encountered. If you have a relevant Word document you would like to have posted on this comments page, such as a version of the protocol you have used in your classroom, or if you would prefer to send your comments or questions in a private message, please write Ingrid Waldron at iwaldron@sas.upenn.edu.

See also a complete list of activities:
Hands-on Activities for Teaching Biology to High School and Middle School Students

 

Comments

Serendip Visitor's picture

Albinism and dragon gentic WS

HI,

I am planning on using these worksheets with some of my advanced students in middle school. DO you have the answer key to the worksheets?

iwaldron's picture

Keys for Activities

We have keys only for a few selected activities (not including this one). If there is a key for a given activity, it is always mentioned in the Teacher Notes. If there isn't a key, the Student Handout and Teacher Notes provide almost all the information you would need to know the answers to the questions. Obviously, a general knowledge of the subject is helpful, so if the topic is unfamiliar you might want to consult a good introductory biology textbook for additional background. If there is no key for an activity you are using, and you would like to inquire about the answer to a specific question, please write me (iwaldron@sas.upenn.edu) or post a comment.

iwaldron's picture

August 2012 revision

The Student Handout has been substantially revised to increase the focus on important concepts of genetics, including how meiosis and fertilization provide the basis for inheritance, dominant and recessive alleles, incomplete dominance, and epistasis. The simulation procedures have been streamlined and clarified to maximize the time available for learning and understanding genetics. In addition, the title has been changed to "Dragon Genetics – Understanding Inheritance" (Previously, this activity was called "Dragon Genetics – Principles of Mendelian Genetics.")

iwaldron's picture

Clarification of Instructions

Each popsicle stick represents a pair of homologous chromosomes. If possible, photocopy the pages for the different chromosomes on different color paper as directed on pages 3-8 of these Teacher Preparation Notes. Once you have cut out the vertical strips of letters, for each of the autosomes and for the sex chromosomes for females, choose any two strips (which will have the same genes, but in many cases different alleles) to paste on the two sides of a popsicle stick. For males, you must match an X chromosome (which has the 5 letters and the + or - for non-fire breather versus fire breather) for one side of the popsicle stick and a Y chromosome (which has only three letters) for the other side of the popsicle stick which will represent the pair of sex chromosomes for a male.

It is important to think in terms of the biological processes of meiosis and fertilization as students do this activity. Once each student has five popsicle sticks (one of each color autosome in one sex chromosome stick), the student drops these sticks on the table to simulate meiosis. The side of the stick that is up represents the chromosome (from each pair of homologous chromosomes) that is in the gamete which will take part in fertilization to form the zygote that develops into the baby dragon. Thus, the alleles on the side of the popsicle stick that is up are the alleles in the egg or sperm and they should be recorded in the appropriate columns of the tables on pages 3 and 4 of the Student Handout; these alleles are then used to determine the phenotypic traits of the baby dragon. In these tables, the genotypes of the parents are the two alleles for each gene on each of the chromosomes.

Ingrid

Yvette Scherer's picture

Dragon Genetics - Sex Linked traits

I used a similar activity - instead of popsicle sticks - cut strips of paper- pairs of homologous chromosomes (pink for maternal set and blue for paternal set of homologous chromosomes); on the 7th set XX for female and XY for male - the X chromosome allele = H for Horn and h for hornless - we kept track of how many males vs female expected; and how many males expected hornless if the females all were heterozygous for Horned and all male parents started out H (horned). It worked well to show hornless males occurred more often in a large population - and that the female X/h chromosome is passed to the male offspring. Good lead in to natural selection.
Students worked in pairs (mom and dad) placing all chromosomes face down on the desk and choosing one of each pair to form the zygote.

Linda's picture

Inversion

If there is an inversion, how do the students identify the trait?

iwaldron's picture

Inversion

For the purposes of this activity, students should assume that the gene has the same effect on a trait even if there is an inversion. In real genomes there might be disruption of gene expression or of the coding sequence, but you will probably want to ignore these possibilities in this context.

Rhonda Williams's picture

Inversion and deletions of genes

How do you pick the phenotype when the alleles do not match or are missing.
Thank you,
Rhonda

iwaldron's picture

Inversions and deletions-too complex for middle schoolers?

 

Dear Rhonda,
 
If I were teaching middle school, I would not use the Dragon Genetics activity we have posted because of its complexities, including inversion and deletion of genes. I think that for middle school students these complexities detract from learning the basic concepts. Therefore, I suggest that you could modify the Word version of the handouts to simplify the posted lab, or you could use one of the simpler activities available on the web. Unfortunately, I don't have appropriate links for you readily available, but one possible starting place would be Dr. Pamela Esprivalo Harrell's "Dragon Genetics" in the January 1997 issue of Science Scope, 20:4, 33-37.
 
Ingrid Waldron

 

 

Rhonda Williams's picture

Question about gene inversions and deletions

With middle school how can I explain the inversion to my class. Angie's comment was helpful because it was confusing on how to get things started.
If you have sQ pairing how do you pick the phenotypic trait
Thanks,
Rhonda

Ingrid Waldron's picture

How to Use the Worksheet -- Response

> Dear Angie,
>
> The key here is to remember that the students work in pairs. One is the
> mom and one is the dad. The mom and dad will each determine their
> genotype for each gene by examining the alleles on the two sides of the
> green popsicle stick and each of the other popsicle sticks. This is the
> information that will go under mom and dad genotypes. Once these
> columns are filled out for the green popsicle stick, the mom and dad
> will each "randomly drop his or her stick on the table". The allele
> that is up on the mom's dropped popsicle stick will be the allele in the
> egg, and the allele that is up on the dad's dropped popsicle stick will
> be the allele in the sperm. The combination of the alleles in the egg
> and sperm give the genetic makeup of the baby, which determines the
> phenotypic trait in the baby.
>
> I hope this helps,
> Ingrid
>

Anonymous's picture

how to use the worksheet

I am preparing to use your dragon genetics activity, but I am unsure
on how to use the worksheet. What goes under mom and dad genotypes
and what goes under alleles in egg and sperm? If I flip the Popsicle
sticks and come up with Aa, which one of the previous columns does
this go into.

Thanks,
Angie

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