Genetics Lab: DNA & Heredity — Breed a 3D creature to see Mendelian genetics work

The useful test is whether an app makes you run the cross yourself rather than just show you a finished example. Genetics Lab does that: you pick parent genotypes across 15 traits, tap Breed, and watch a real Punnett square resolve into a 3D creature's actual coat, eyes and wings. It covers the monohybrid cross through dihybrid ratios, non-Mendelian patterns and population genetics in 34 lessons, free on iOS and Android.

A Punnett square lines up one parent's possible alleles across the top and the other's down the side, then fills each cell with the combination that lands there. Each cell represents one equally likely outcome, so counting how many cells show a given genotype or phenotype gives you its probability directly. Genetics Lab's Cross Lab builds this grid from whatever genotypes you choose, so the square you see always matches the cross you actually set up.

A genotype is the pair of alleles an organism carries for a gene — for example Bb, one dominant and one recessive copy. A phenotype is the trait you can actually observe, such as a particular coat colour. Two different genotypes can share one phenotype whenever a dominant allele masks a recessive one, which is why a Punnett square tracks genotypes first and phenotypes second.

A dihybrid cross follows two genes at once, and the 9:3:3:1 ratio comes from the independent assortment of those genes — each gene's alleles sort into gametes without affecting the other gene's alleles. Multiplying the probabilities for each gene separately across sixteen total possible offspring combinations produces exactly that split. Genetics Lab's World 2 walks through the product rule and the sum rule that explain the arithmetic behind the ratio, with the Cross Lab letting you verify it on an actual two-trait cross.

Incomplete dominance blends two phenotypes into an intermediate form, the classic example being red and white flowers producing pink offspring. Codominance instead expresses both alleles fully at once, so a heterozygous organism shows both parent traits side by side rather than a blend — a spotted coat pattern showing both colours is a typical example. Genetics Lab's Beyond Mendel world covers both patterns, along with multiple alleles and sex-linked inheritance, as the cases that go past the basic dominant-recessive rule.

The Hardy-Weinberg equation predicts how allele and genotype frequencies should remain stable across generations in an idealised population — one with no mutation, migration, selection or genetic drift. It gives biologists a baseline to compare real populations against, since a population's frequencies drifting away from that prediction signals one of those real forces at work. Genetics Lab's Population Genetics world introduces the equation alongside allele frequencies, DNA structure and mutation.

The Glimmerbeast is the fictional creature every cross in the app is run on, with 15 breeding traits — coat colour, ear shape, eye colour, tail length, body size, horns, wings, coat pattern and glow among them — controlled by roughly 40 alleles. Using an invented creature keeps every lesson in a safe sandbox for learning heredity mechanics, with no human genetics and no medical framing anywhere in the app.

Yes. It is free to download on the App Store and Google Play, with the first world, a limited set of breeding traits, part of the Collection and the Daily Cross available at no cost, and ads shown to support the free content. A Pro subscription unlocks the remaining worlds and lessons, all 15 breeding traits, the full 120-challenge Collection, the AI genetics tutor and an ad-free experience.

It explains a specific genotype, cross or ratio in plain language when a result doesn't match what you expected — for instance, why a cross produced a 3:1 ratio instead of 1:1. It answers the problem actually in front of you rather than giving a generic genetics lecture, and the app asks for your permission before the first AI request goes out.

No. The course starts at the definition of a trait and builds up one Punnett square at a time toward dihybrid crosses, non-Mendelian inheritance and population genetics. It's built for high school and college students working through Mendelian genetics, homeschool learners without lab equipment, and anyone who wants alleles and probability to click.