From the molecule to the chromosome
The DNA Structure 3D Model builds the double helix from a single nucleotide and lets you measure it, as Watson and Crick did from Photo 51. The Virtual Living Cell follows the human insulin gene through transcription and translation, codon by codon, and shows what a point mutation does to the protein. The Interactive Codon Chart and DNA to Protein Translator puts the genetic code itself on a wheel and a table, translates any sequence you paste in, and names every kind of mutation, with sickle cell, β-thalassemia and cystic fibrosis as real examples.
Chromosomes on the move
The Mitosis Simulator counts chromosomes, chromatids and DNA through every phase of the cell cycle. The Meiosis Simulator pairs homologous chromosomes, crosses them over and deals out four different gametes, so you can see where genetic variation comes from and what nondisjunction does.
Predicting the offspring
The Interactive Punnett Square Calculator takes those gametes and crosses them: one, two or three genes, sex-linked genes and ABO blood types, with every offspring drawn as a pea, a fruit fly or a person on a pedigree. Grow a generation, compare it with the predicted ratio and run a chi-square test, as in Mendel's and Morgan's own experiments.
Which simulation for which topic
| Topic | Open |
|---|---|
| DNA structure, base pairing, Chargaff's rules | DNA Structure 3D Model |
| The genetic code, DNA to mRNA to protein, types of mutation | Interactive Codon Chart and DNA to Protein Translator |
| Protein synthesis inside a working cell | Virtual Living Cell |
| The cell cycle and mitotic index | Mitosis Simulator |
| Crossing over, independent assortment, gene mapping | Meiosis Simulator |
| Punnett squares, dihybrid and sex-linked crosses, chi-square | Interactive Punnett Square Calculator |
Using them in class
Each simulator has an Experiment mode with a real practical, such as scoring Sordaria asci for map units or measuring the helix from an X-ray photograph, and a chi-square test where the course calls for one, such as testing a corn ear against 9 : 3 : 3 : 1 in the Punnett square calculator. A pedigree analyser is being built next.
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