Mendelian laws - exploring the "garden lab"

Observe phenotypes, compare them with the expected values in the Punnett square, and test them in simulations. Use your findings to formulate three general rules.

Gamete formation for the Punnett square
The Punnett square is a table used to determine all possible genotype combinations of the offspring from the gametes of both parents. The rows represent the gametes of parent 1, the columns represent the gametes of parent 2, and the cells combine the corresponding alleles. This allows you to derive expected values for genotype and phenotype ratios.

In diploid organisms, genes occur in pairs as two alleles (for example Y and y). During meiosis, these alleles separate so that each gamete receives only one allele per gene. A homozygous genotype (for example YY) can therefore contribute only one allele variant to the gametes (Y), while a heterozygous genotype (for example Yy) can contribute two possible variants (Y or y). The Punnett square then combines the gametes of both parents systematically.

A monohybrid cross examines the inheritance of one single gene (one trait) with two alleles. A dihybrid cross, by contrast, investigates the inheritance of two genes (two traits) at the same time, for example Y/y for seed color and R/r for seed shape. In heterozygous parents this leads to more gamete variants, such as YR, Yr, yR, and yr, because the alleles of both genes are distributed into the gametes.
Simulation: Meiosis I & II (gamete formation)

Simulation

Set the cross -> build the Punnett square -> run the simulation.
Parent 1
Parent 2

Punnett square

Phenotype distribution

No simulation yet.

Genotype frequencies

Derive rules from genotype and phenotype ratios.
GenotypeCountShare