Level of life
Gene
A basic unit of heredity: a stretch of DNA with instructions for a product such as a protein or a functional RNA.
Genetics
How traits are inherited and how genes vary.
Genetics is the study of genes and how traits, like eye color, are passed from parents to children.
Geneticists study how alleles are inherited, how variation arises through mutation, and how genotype and environment together shape traits.
From Mendelian ratios to genome-wide variation, genetics links differences in DNA sequence to traits, disease and evolution.
Big questions
- Why do children resemble their parents, but not exactly?
- How do changes in DNA cause disease?
- How much do people differ genetically?
Key ideas
Open any idea in the knowledge graph to see what it connects to, here and in other fields.
Idea or model
Allele
One of two or more versions of a DNA sequence at the same place in the genome. You inherit one from each parent.
Idea or model
Genotype
The particular variants an individual carries at a location in the genome, often written as letters such as Bb.
Idea or model
Phenotype
Observable traits such as height or blood type, shaped by both genotype and environment.
Idea or model
Dominant and recessive
A dominant allele shows its effect with one copy; a recessive allele shows its effect only with two copies.
Idea or model
Mendelian inheritance
Mendel's pea crosses showed that traits are inherited as separate units, giving predictable ratios such as 3 to 1.
Idea or model
Punnett square
A grid that predicts the possible offspring genotypes from a cross between two parents.
Structure
Chromosome
A single DNA molecule packaged with proteins. Human cells usually carry 23 pairs, 46 chromosomes in all.
Process
Mutation
A change in a DNA sequence. Mutations arise from copying errors or damage, and their effects range from none at all to disease.
Idea or model
Human genome
The full DNA sequence of a human. Drafts were published in 2001, and the first gap-free sequence in 2022.
Idea or model
Human genetic variation
Differences in DNA between people. A 2015 study reconstructed the genomes of 2,504 people from 26 populations.
Health condition
Sickle cell disease
An inherited blood disorder caused by a variant in the HBB gene that changes one amino acid in hemoglobin.
Health condition
Cystic fibrosis
An inherited condition caused by variants in the CFTR gene, in which thick mucus damages the lungs, digestive system and other organs.
Explore it in the labs
Simulation
Pair bases, follow a real human gene from DNA to protein, make mutations, and predict inheritance with Punnett squares.
- Genetics
- Molecular Biology
- Biochemistry
Simulation
Watch natural selection and genetic drift change how common a gene version is, in small and large populations side by side.
- Evolution
- Genetics
- Ecology
Timeline and explorer
A sourced timeline from the double helix to CRISPR therapies, eight technologies labeled established or emerging, and a PCR model.
- Biotechnology
- Synthetic Biology
- Genetics
Current research
Search published papers and preprints in Genetics, with clear labels for reviews, primary research, clinical trials and preprints.
Search papers in GeneticsSources & further reading
The explanations on this page are our own summaries of these sources. Follow a link to read the original; if anything here disagrees with it, the original wins. How we choose and check sources.
Biology 2e (opens the original in a new tab)
OpenStax (2018). OpenStax, Rice University.
Free introductory college textbook.
TextbookEducationalLicence: CC BY-NC-SA 4.0 (linked, not reused)
Experiments on Plant Hybrids by Gregor Mendel (opens the original in a new tab)
Abbott S, Fairbanks DJ (2016). Genetics 204:407-422.
A modern English translation of Mendel's 1866 paper.
Peer-reviewedTranslationWhat are the different ways a genetic condition can be inherited? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalWhat is a gene? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalAllele (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalGenotype (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalPhenotype (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalDominant Traits and Alleles (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalRecessive Traits and Alleles (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalChromosome (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalMutation (opens the original in a new tab)
National Human Genome Research Institute. Talking Glossary of Genomic and Genetic Terms. National Human Genome Research Institute, NIH.
ReferenceGovernment sourceEducationalWhat kinds of gene variants are possible? (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducational
Show 9 more sourcesHide 9 sources
Initial sequencing and analysis of the human genome (opens the original in a new tab)
Lander ES, Linton LM, Birren B, et al. (2001). Nature 409:860-921.
Peer-reviewedPrimary researchThe sequence of the human genome (opens the original in a new tab)
Venter JC, Adams MD, Myers EW, et al. (2001). Science 291:1304-1351.
Peer-reviewedPrimary researchThe complete sequence of a human genome (opens the original in a new tab)
Nurk S, Koren S, Rhie A, et al. (2022). Science 376:44-53.
The Telomere-to-Telomere consortium's gapless human genome assembly.
Peer-reviewedPrimary researchA global reference for human genetic variation (opens the original in a new tab)
1000 Genomes Project Consortium, et al. (2015). Nature 526:68-74.
Peer-reviewedPrimary researchSickle cell disease (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalGene mutations in human haemoglobin: the chemical difference between normal and sickle cell haemoglobin (opens the original in a new tab)
Ingram VM (1957). Nature 180:326-328.
Traced sickle cell hemoglobin to a single amino acid change.
Historical paperPrimary researchSickle cell anemia, a molecular disease (opens the original in a new tab)
Pauling L, Itano HA, Singer SJ, et al. (1949). Science 110:543-548.
Historical paperPrimary researchCystic fibrosis (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducationalCFTR gene (opens the original in a new tab)
MedlinePlus Genetics. MedlinePlus Genetics. U.S. National Library of Medicine, NIH.
ReferenceGovernment sourceEducational