Punnett Square Generator
Understanding Genetics & Punnett Squares
A Punnett Square is a grid used by biologists to determine the probability of an offspring having a particular genotype. It visualizes how alleles from parents combine during fertilization.
- Alleles: Different versions of a gene (e.g., 'A' for dominant, 'a' for recessive).
- Genotype: The genetic makeup of an organism for a trait (e.g., AA, Aa, aa).
- Phenotype: The observable characteristic resulting from a genotype (e.g., tall, short).
- Homozygous: Having two identical alleles for a trait (e.g., AA or aa).
- Heterozygous: Having two different alleles for a trait (e.g., Aa).
- Dominant Allele: An allele that expresses its trait even when only one copy is present (e.g., 'A' in Aa results in the dominant phenotype).
- Recessive Allele: An allele that only expresses its trait when two copies are present (e.g., 'a' in aa).
Mendel's Laws:
- Law of Segregation: During gamete formation, the two alleles for each gene separate so that each gamete carries only one allele for each gene.
- Law of Independent Assortment: Genes for different traits can segregate independently during the formation of gametes (applies to genes on different chromosomes or far apart on the same chromosome).
How to Use This Calculator:
- Enter the genotype for Parent 1 (e.g.,
Aafor one trait,AaBbfor two traits,AaBbCcfor three traits). Use one capital and one lowercase letter for heterozygous traits (e.g., Aa), two capitals for homozygous dominant (AA), and two lowercase for homozygous recessive (aa). - Enter the genotype for Parent 2 in the same format. Max 3 traits (6 letters).
- Click "Generate Square".
- The results will show parental gametes, the Punnett square, and genotypic/phenotypic ratios.