The Virtual Genetics Lab II (VGLII) is an improved version of the highly successful genetics simulation software, the Virtual Genetics Lab (VGL). The software allows students to use the techniques of genetic analysis to design crosses and interpret data to solve realistic genetics problems involving a hypothetical diploid insect. This is a brief outline of the program and its new features; details are available at http://intro.bio.umb.edu/vgl/.

A student begins by selecting from one of several Problem Files assigned by their instructor. The software then randomly generates a problem by choosing from the models allowed in the Problem File and instantiating the model by choosing from a large set of traits and characters. The student's task is to determine the genetic mechanism underlying the inheritance of these traits by choosing insects for crossing and observing the resultant offspring. The process of solving these problems includes two elements that are typically not present in pencil-and-paper genetics problems: choosing which individuals to cross and determining whether a cross produces useful information or not. A sample problem session is shown in Figure 1.

Figure 1.

A sample VGL session. Cage 1 shows the starting “field population” where the insects have either blue or yellow bodies; male and female symbols indicate organisms that can be selected for crossing. Cage 2 contains the offspring from a cross of two blue-bodied insects from Cage 1; this cross is not particularly informative. Cage 3 contains the offspring of two yellow-bodied insects from Cage 1; it shows clearly that body color is sex-linked and that blue is recessive to yellow.

Figure 1.

A sample VGL session. Cage 1 shows the starting “field population” where the insects have either blue or yellow bodies; male and female symbols indicate organisms that can be selected for crossing. Cage 2 contains the offspring from a cross of two blue-bodied insects from Cage 1; this cross is not particularly informative. Cage 3 contains the offspring of two yellow-bodied insects from Cage 1; it shows clearly that body color is sex-linked and that blue is recessive to yellow.

Because each problem is generated randomly, each is different, thus allowing an almost limitless opportunity for practice. Furthermore, genetic models can include autosomal or sex-linked (XX/XY or ZZ/ZW) genes, and many alleleic interactions (simple, incomplete, circular, and hierarchical dominance). VGLII includes the following improvements:

  • Multiple genes. Problems can include one to three genes. These genes can be linked; genes can also interact via epistasis or complementation.

  • Internationalization. All text can be displayed in English, Spanish, or French.

  • Model Builder. To help students scaffold their work, they can enter parts of their developing genetic model into the Model Builder (see Figure 2).

  • Grading. An instructor can open students' work and compare each of the students' answers in the Model Builder with the correct model. This allows instructors to assign VGLII problems for homework, providing a very large set of customized unique genetics practice problems that can be easily graded. Figure 3 shows the grading result for the session from Figures 1 and 2.

Figure 2.

Model Builder. The student enters his or her answer by choosing from the menus in the Model Builder to fill in components of the genetic model they are discovering. The complete answer includes both the genetic model and the cage(s) that support that model.

Figure 2.

Model Builder. The student enters his or her answer by choosing from the menus in the Model Builder to fill in components of the genetic model they are discovering. The complete answer includes both the genetic model and the cage(s) that support that model.

Figure 3.

Grading display. This shows the correct model as well as the student's answer; the instructor then can assign points as appropriate.

Figure 3.

Grading display. This shows the correct model as well as the student's answer; the instructor then can assign points as appropriate.

Problems in VGLII cover a wide range of difficulty, from simple practice for a high school student to challenging work for a graduate student. With the ability to grade students' work, VGLII will provide a huge number of challenging genetics problems as well as a novel assessment method for students at a wide range of levels.

The VGLII program, Problem Files, and sample lab manuals are available free of charge at http://vgl.umb.edu.

Reference

Reference
White, B., Bolker, E., Koolar, N., Ma, W., Maw, N. & Yu, C. (2007). The virtual genetics lab: a freely-available open-source genetics simulation. American Biology Teacher, 69, 694–697.