What does haplotype mean?
A haplotype is a combination of alleles or DNA variants that occur together on the same chromosome and are usually inherited as a unit. The term is especially common in population genetics, where researchers compare mitochondrial, Y-chromosomal, and other chromosomal haplotypes to study ancestry, migration, selection, and genetic variation. It is also important in immunology, particularly in descriptions of HLA haplotypes, which refer to linked sets of human leukocyte antigens. A haplotype should not be confused with a genotype, which encompasses an organism's broader genetic constitution, or with a phenotype, which describes an observable characteristic. In ordinary use, haplotypes often distinguish closely related DNA sequences at particular sites or larger chromosomal regions. The word comes from Greek roots meaning “single” and “form,” reflecting its early association with a chromosome carrying one set of genetic information.
nounA combination of alleles inherited together on the same chromosome, especially a set of closely linked genetic variants that tend to be transmitted as a unit.
- A combination of alleles or DNA variants occurring together on the same chromosome or within a linked chromosomal region, inherited as a unit.
"The study compared mitochondrial haplotypes to reconstruct the population's maternal ancestry."
"Researchers identified a previously unknown haplotype associated with resistance to the disease."
"The donor's HLA haplotype was compatible with the recipient's tissue type."
The plural haplotypes is standard in scientific and academic writing.
"Several haplotypes were shared by individuals from the same geographic region."
The mitochondrial haplotype carried by your cells can trace your maternal ancestry deep into the past.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does haplotype come from?
Haplotype entered biological terminology in the early twentieth century through the combination of Greek haplos, meaning “single,” and typos, meaning “form,” so that it originally referred to a single chromosomal form. It was subsequently specialized in genetics to mean the particular combination of alleles carried by a chromosome. Its relatives haploid and haploidy use the same Greek element for “single,” while diploid combines a different numerical prefix with the same Greek noun for “form.”
Related word forms
How haplotype is actually used
This is a technical term used chiefly in genetics, genomics, population biology, immunology, genealogy, and related fields. It is not interchangeable with genotype, which refers more broadly to an organism's genetic constitution.
Easily confused with haplotype
A haplotype is a particular combination of linked alleles, whereas a genotype describes an organism's complete genetic constitution at the loci being considered.
A haplotype is a genetic or allelic pattern, whereas a phenotype is an observable characteristic produced by genetic factors and their interaction with the environment.