The term haplotype is a contraction of the term 'haploid genotype'. In genetics, a haplotype (from the Greek: ἁπλοῦς, haploûs, "onefold, single, simple") is a combination of alleles at multiple loci that are transmitted together on the same chromosome. Haplotype may refer to as few as one locus or to an entire chromosome depending on the number of recombination events that have occurred between a given set of loci.
In a second meaning, haplotype is a set of single nucleotide polymorphisms (SNPs) on a single chromatid that are statistically associated. It is thought that these associations, and the identification of a few alleles of a haplotype block, can unambiguously identify all other polymorphic sites in its region. Such information is very valuable for investigating the genetics behind common diseases, and has been investigated in the human species by the International HapMap Project. 1, 2
Many genetic testing companies use the term 'haplotype' to refer to an individual collection of short tandem repeat (STR) allele mutations within a genetic segment, while using the term 'haplogroup' to refer to the SNP/unique-event polymorphism (UEP) mutations which represents the clade to which a collection of potential haplotypes belong. 3
Reference:- The International HapMap Consortium (2003). "The International HapMap Project". Nature 426: 789–796. doi:10.1038/nature02168.
- The International HapMap Consortium (2005). "A haplotype map of the human genome". Nature 437: 1299–1320. doi:10.1038/nature04226.
- Facts & Genes. Volume 7, Issue 3
