Pedigree Go Fish.

“Do not, then, my friend, keep children to their studies by compulsion but by play.”

INTRODUCTION

Among the topics that are perplexing for genetics students is segregation analysis. Pedigrees are examined for clues to the most likely method of transmission (autosomal versus X-linked versus mitochondrial, dominant versus recessive). A primary source of confusion for students is that answers are not always clear. Judgments must be made using methods such as process of elimination (a trait skipping generations is not likely to be due to a dominant allele) and the preponderance of evidence (sex-linked traits often have a sex bias among affected individuals). The ambiguity of answers is often uncomfortable to students in undergraduate genetics courses.

As discussed in a previous board game publication (1), games are an engaging way to improve student learning and retention. There are also online tools to assist the teaching of pedigree analysis such as the engaging “PI: Pedigree Investigator” (http://learn.genetics.utah.edu/content/addiction/pi/) and the Genetics Cognitive Tutor (http://www.cs.cmu.edu/~genetics/). However, the author was unable to identify any in-class aids for this specific topic. Pedigree Go Fish was constructed as an option for active, instructor-supervised classroom reinforcement of segregation analysis. The expectation is that students have already been introduced to the topic by lecture or other means. The game is intended to provide practice and aid in retention of the principles. The activity targets undergraduates in either majors or nonmajors genetics courses, but can be applied across levels with appropriate instructor guidance. The game is easily prepared and takes approximately 30 minutes.

PROCEDURE

Required materials

Preparation primarily consists of printing the cards and cutting them out, which takes about 30 minutes. The game cards and instruction sheet are provided in Appendix 1. A printer capable of printing on both sides of the paper is preferable as cards are double-sided. It would also be preferable to print on color card stock if possible to give a feel closer to real playing cards. Printing on colored paper allows common methods of transmission (e.g., autosomal recessive) to have more examples while maintaining books of four cards. It is recommended that colors be chosen so that they are visibly different to those with red-green colorblindness (e.g., red and blue). Note that the color number is written on the cards in case there are still issues with card color—so a player with other forms of colorblindness, such as achromatopsia, would still be able to identify card colors by number. An example card is presented in Figure 1. Cards could be laminated if desired, but may become overly slippery on table surfaces. Instructions should also be printed out for students who have forgotten the rules to Go Fish.

FIGURE 1

The front (left) and back (right) of a sample card. Note that the color is written out as a number so that students with difficulty discerning color differences (e.g., colorblindness or color deficiency) will have an easier time identifying the colors.

Instructor guidelines

It works best for students to divide into groups of three or four if possible. If student teaching assistants or previous students are available, they make good fill-in players as necessary. The goal of each player is to collect the most “sets” of pedigrees. A set consists of four cards of a single color for a single method of inheritance (e.g., four “red and autosomal dominant cards”).

The cards are shuffled, and each player is dealt four cards, which are placed on the table in front of them with the pedigree facing up so that all players can see all dealt pedigrees. Remaining cards are spread in the center of the table with pedigree sides up.

Play starts to the dealer’s left. Each turn, a player draws up to a total of four cards from the draw pile. If the player already has four or more cards, they may pick one extra. The player then asks another player if they have any cards of a particular method of inheritance which the requestor already has. For example, if the requestor has three “blue sex-linked recessive” cards, they may ask one other player if that have cards of that type. If the other player does have any cards of that type, they must pass all cards of that type to the requestor. If the player does not have cards of that type, they say so; if any player identifies a card of that type in the requested player’s hand, they can call it and receive those cards. So if player A requests “blue sex-linked recessive” from player B, player B says they do not have any, and player C sees a pedigree in player B’s hand that matches that type, player C may call that card and claim it. If no player declares a match, the requestor can draw an extra card from the draw pile. Play proceeds to the left.

Play continues until all books are collected. The winner is the player with the most books. In the event of a tie, suitable tie breakers can be devised by the instructor. For example, the instructor might pick a random card and challenge the players to identify the most likely method of inheritance.

CONCLUSION

The game was play tested in two iterations of a nonmajors genetics course and one iteration of a majors genetics course. No difference in play style was observed between majors and nonmajors groups. The primary difference from Go Fish is that all cards must be laid out in front of each student in such a way that pedigrees, but not method of transmission, are visible so that students can employ their developing understanding of segregation analysis to their advantage. Although students found the game play somewhat challenging, they also engaged in competition which spurred them to think carefully about the clues presented in the pedigrees and overcome their discomfort with some degree of uncertainty to the answers. In some cases, students did resort to guessing, using traditional tactics of Go Fish. However, more successful students were observed actively targeting whom they asked for a type of card based upon the information in the pedigrees of opponents. As an incentive to increase applying of pedigree rules, picks from a small “prize bin” of miniature rubber duckies were provided to winners at each table. For tables that finished earlier than others, second rounds were allowed, including additional prizes.

Although classroom sizes were too small (<20 students each) to allow rigorous statistical analysis, students anecdotally expressed greater confidence in their ability to identify the most likely method of transmission for given cards. Some students even identified one pedigree that was incorrect for its stated method of transmission, which has been subsequently revised.

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