What is CGS?

CGS gives students the opportunity to perform test crosses with model organisms, much like a geneticist would do in a modern laboratory. Instructors can set the parameters for the populations that the students investigate, such as the number and type of traits in a population, the modes of inheritance, trait linkage, etc. It is then up to the students to determine which crosses to perform, and to interpret the data that they collect. CGS can be used as a primary laboratory module for introductory biology or genetics courses, or as a supplement to a hands-on genetics module with real organisms.

How do I get started with the Instructor Interface?

  1. If you have an account, use the link on the upper right of the screen to launch CGS. If not, you can click here to request one.
  2. Follow the menu options to log in as an instructor. Once you have logged in, you can create a new student account. Each student account contains a set of populations that you can customize. If you like, you can have CGS randomize some or all of the genetic properties within your populations.
  3. Tell your students to log in to your new account. They will need to know your CourseID and the name of your account to access the populations that you created.

Frequently asked questsions

Why use a computer simulation to teach genetics?

There are several advantages to using a computer simulation to learn genetics, most importantly:

  • 1. Students can examine many generations of genetic inheritance without the time restrictions that are inherent with living organisms. 
  • 2. A computer simulation is inexpensive and does not require a lot of resources.
  • 3. No organisms are created or destroyed in the computer simulation.

CGS offers three model organisms for analysis: Drosophila, Arabidopsis, or Mouse.

Is CGS similar to GCK?

CGS has many advantages over GCK (Bioquest, 1994) and can run on modern PC or Mac hardware. CGS is not affiliated with Bioquest.


How do I use CGS?

Students and instructors can access the program by going to

CGS is web-based. This offers several advantages, mainly:

  1. Students can access the program from outside of class if needed.
  2. There is no software to install or update. Runs on any computer with a Flash-enabled web browser. 
  3. Instructors can quickly set up the program for use on multiple computers.
  4. Instructors can easily access all student information from one computer.

How are instructor accounts obtained?

Instructors who are interested in using CGS for their course should send a request using the link above. Instructor accounts are only given to teachers and course coordinators, and are not given to students.


Can CGS be used without an internet connection?

A stand-alone version of CGS can be made for Windows or Mac if there is interest. If this is something you would like to see, please use the feedback link above.


Can I try it out now?

Even if you do not have an account, you can access the program through the demo page.


How can CGS be customized?

CGS allows an instructor to create populations with specific phenotypes and modes of inheritance for students to analyze. Alternatively, an instructor can set CGS to randomize these settings each time a new students logs in. To create a new student account, instructors should log in using the 'Instructor Login' link at the top of this page. Enter a new account name and press the 'New' button to proceed to the settings screen.

The genetic properties for each population can be selected as shown in the examples below. Use the slider on the left side of the screen to choose the number of populations to create. There can be up to 10 independent populations created for each student account.

Up to three independent segregating traits can be created per population. For each individual trait, a specific mode of inheritance can be selected from the drop-down menu, or a mode can be randomly assigned. Traits can be linked to the same chromosome with a specified recombination frequency by using the drop-down menus.

CGS can randomize the mode of inheritance and phenotypes between students who log in with the same student account. This way, a small number of accounts can be sufficient for a large number of students. Instructors can log in to access the "answers" for each student (see below).

How do students access the program?

To use CGS, students will need to know their instructor's "Course ID" and the "Student Account" that has been assigned to them. Students are given a password when they first log in. This password will allow saved populations to be retrieved at a later time if needed.


How can instructors access the details for each student?

From the instructor menu, click on a student's name to get information about which populations the student has examined, which phenotypes are dominant/recessive, the modes of inheritance for each population, etc.

Information for Instructors

  • Try a demo account
  • Request an Instructor Account
  • Renew your account online

  • Additional resources

    Instructor manual and example course material - A comprehensive manual and other materials are available to instructors who have an account. Click the "Instructor Resources" link from within CGS to access this material.  Please send an email to info at cgslab dot com for additional information or have any questions. Feedback is always welcome.