Vision Statement

The jsVirtual Genetics Lab (jsVGL) is a simulation of transmission genetics that approximates, as closely as possible, the hypothesis-testing environment of genetics research.  In this lab, students cross hypothetical creatures and examine the progeny in order to determine the mechanism of inheritance of a particular trait.  As in actual research, it is not possible to 'see the answer' - the student must decide for herself when she has collected enough data to be sure of her model.  The goal is to have students understand the logic of genetic analysis - how one can use crosses to determine how a trait is inherited and reinforce their understanding of transmission genetics.

jsVGL also allows students to enter their answers - their model of how their traits are inherited - in a form that allows their work to be automatically graded by their instructor. E-mail me Brian.White@umb.edu for details.

jsVGL is a browser-based version of the stand-alone application VGLII, which, in turn is based on the original Mac application, the Genetics Construction Kit (GCK). Because it is becoming increasingly difficult to develop cross-platform applications, I will no longer be supporting the stand-alone VGLII app and will focus my development efforts on jsVGL.

jsVGL is developed to work on the Google Chrome browser but may be compatable with other browsers as well.

VGLII Philosophy and Mission

This program is based on the Genetics Construction Kit (GCK) developed by BioQUEST. The original GCK was written in the mid-1980's and ran on the Macintosh Classic operating environment. jsVGL is designed as a newer version of GCK that runs in a web browser and that takes advantage of the improved user interface available on newer computers.

In order that the exercise is based on the logic of genetic analysis rather than student's ability to search the internet, the creature under study is hypothetical, the traits are assigned randomly, and the mode of inheritance differs with each run of the program.  Traits can be either autosomal or sex-linked (with XX females and XY males or with ZZ males and ZW females) and simply dominant or co/incompletely dominant.  The form of the trait which is dominant, recessive or seen in the heterozygote will also be determined randomly.  The instructor can customize the program to limit the range of possibilities that the students could face.  In this way, students can be gradually introduced to problems of increasing complexity.

In a real genetics lab, students have to deal with real-world creatures that die, fail to mate, or escape.  In addition, most creatures have generation times of several weeks or months, thus limiting the number of crosses an individual can perform during a semester.  Although these real-world constraints have educational value, the point of the jsVGL is to understand the logic of genetic analysis rather than the technical details.  The jsVGL allows the students to maximize the number of crosses they can perform, thus maximizing their chance to understand the underlying analysis.

In this lab, students have to decide:

In order to perform a cross, the students select male and female parents of their choice from any generation and click the "Cross" button.  The program keeps track of the genotypes of the parents and generates their offspring probabilistically.  In that way, the phenotypic ratios of the offspring will approximate, but not necessarily be identical to the classic 1:1, 1:2:1, and 1:3 ratios.  The students have to decide for themselves whether their data are consistent or inconsistent with their expected ratios.  While some crosses will generate useful information, others will be uninformative; the students will have to choose what to cross and what to make of the results.

Cross results are presented in a table sorted by phenotype with a display of the numbers of male and female individuals of each phenotype.  In addition, a thumbnail image in the table gives a visual display of the phenotype.

Because of this freedom to choose what to cross, different student groups will adopt different strategies for analysis.  Some will plan each cross carefully and analyze the results as they go along while others will do many haphazard crosses and try to sort out the results later.  jsVGL thus accommodates the wide range of successful strategies and does not limit the students to one particular pattern.

Although jsVGL is designed so that students cannot 'look behind the scenes' to see the underlying model or the genotypes of individuals, the instructor can generate problems in 'practice mode'.  In this mode, students are able to click on individuals and see their genotypes as well as the underlying genetic model.  This mode is designed for the beginning students to help familiarize them with the program and the most basic genetic analysis.

Finally, the program has several important software features: