Life and health

Haplogroup L1c1 (mtDNA)

Haplogroup L1c1 (mtDNA), a subclade of African haplogroup L1c, is a Central African maternal lineage whose subclades mark the shared prehistory and divergence of Bantu-speaking farmers and Western Pygmy hunter-gatherers.

Haplogroup L2c2 (mtDNA)

Haplogroup L2c2 (mtDNA) is a subclade of the West and Central African maternal lineage L2c, one of four L2 clades; L2c dates to about 20,000 years ago and appears in West Africa, North Africa, and the African diaspora.

Haplogroup L3b2 (mtDNA)

Haplogroup L3b2 (mtDNA) is a subclade of African maternal haplogroup L3b, defined by 34 PhyloTree mutations including 13105G and 16124C, showing a West African signal with eastward spread linked to the Bantu expansion.

Oct 20, 2026

Haplogroup M1a2 (Y-DNA)

Haplogroup M1a2 (Y-DNA) is a paternal subclade of haplogroup M (M-P256), defined by SNPs Z30928, Z31007, and Z31146 (formerly P94), found mainly in New Guinea and eastern Indonesia; distinct from the mtDNA clade M1a2.

Oct 20, 2026

Haplogroup O1a1 (Y-DNA)

Haplogroup O1a1 (Y-DNA), also called O1a1-P203 in older nomenclature, is a subclade of O1a-M119 defined by B384/Z23193, concentrated in southern China, Taiwan, and Island Southeast Asia, with a Neolithic expansion about 9.79 kya.

Haplogroup R1a

Haplogroup R1a (R1a) is a human Y-chromosome paternal lineage defined by the M420 mutation, reaching over 40% in Poland and Russia and spread with Indo-European languages.

Haplogroup R1a1 (Y-DNA)

Haplogroup R1a1 (Y-DNA), also R1a-M459/SRY10831.2, a subclade of R1a-M420; its R1a1a-M17 branch spans East Europe to South Asia, with Z282 in Europe, Z93 in Central/South Asia, Viking and Ashkenazi Levite sub-lineages.

Haplogroup R1b

Haplogroup R1b (R-M343), also called R1b-M269 in its dominant European form, is the most common Western European Y-chromosome lineage, about 110 million men; it spread with Bronze Age steppe migrations, with subclades U106, P312, DF27, and Z2103.

Haplogroup T1a1 (Y-DNA)

Haplogroup T1a1 is a rare subclade of the Y-chromosome haplogroup T1a (T-M70), an ancient paternal lineage found mainly in West Asia and interpreted as Near Eastern in origin.

Oct 20, 2026

Haplogroup T1a2 (Y-DNA)

Haplogroup T1a2 (Y-DNA), also called T-L131, is a rare subclade of paternal haplogroup T (M70) within T1a, dated by YFull to about 15,600 years formed and 10,900 years TMRCA, found scattered from Arabia and the Caucasus to Europe, distinct from the unrelated mtDNA clade of the same name.

Haplogroup X (mtDNA)

Haplogroup X is a human mitochondrial DNA maternal lineage with branches X1 and X2, and X2a is one of the five founding Native American haplogroups.

Haploidentical bone marrow transplantation

Haploidentical bone marrow transplantation is a form of allogeneic stem cell transplantation using a half-HLA-matched relative, available to the roughly 70% of patients lacking a fully matched sibling donor.

Haploidentical hematopoietic cell transplantation

Haploidentical hematopoietic cell transplantation (haplo-HCT) is an allogeneic stem cell transplant using a half-matched family donor to treat hematologic diseases, available to over 95% of patients.

Haploidentical stem cell transplantation

Haploidentical stem cell transplantation is a form of stem cell transplant in which the donor, almost always a family member, shares exactly half of the recipient's HLA antigens.

Haploinsufficiency

Haploinsufficiency: a dominant disease mechanism in which one functional gene copy cannot produce enough gene product for normal function, underlying disorders like Dravet syndrome (SCN1A) and 22q11 deletion syndrome, and distinct from dominant negative effects.

Haplomitriopsida

Haplomitriopsida is the earliest-diverging class of liverworts (Marchantiophyta), sister to all others, containing Haplomitrium, Treubia, and Apotreubia in orders Calobryales and Treubiales, about 18 species with plesiomorphic traits.

Haplopappus

Haplopappus, known in Spanish as bailahuén, is a genus of about 75 species of flowering plants in the daisy family, native mainly to Chile and used in Andean traditional medicine.

Haplorhini

Haplorhini, the dry-nosed primates, is the primate suborder containing tarsiers and anthropoids (monkeys and apes), sister to Strepsirrhini; defined by a dry nose, postorbital septum, and retinal fovea, with divergence from strepsirrhines dated roughly 58–77 mya.

Haplosporidium

Haplosporidium, a genus of spore-forming haplosporidian parasites of molluscs; H. nelsoni (MSX, formerly Minchinia nelsoni) devastated eastern oysters from Delaware Bay 1957 onward, is salinity-limited, and lacks a demonstrated direct transmission route.

Haplosporidium nelsoni

Haplosporidium nelsoni, formerly Minchinia nelsoni, is the haplosporidian protozoan causing MSX disease in eastern oysters. First seen in Delaware Bay in 1957, it killed 90–95% of oysters there and in lower Chesapeake Bay; its life cycle and alternate host remain unknown.

Haplotype

Haplotype: a set of DNA variants on a single chromosome inherited together because recombination between them is rare; spans one or more genes. Central to HapMap tag-SNP association studies and to phasing in diploid genome sequencing.

Haplotype reconstruction

Haplotype reconstruction determines which variants in a diploid genome occur together on each chromosome copy, using molecular, genetic, or population-based methods to produce phased haplotypes from sequencing data.

Haptocorrin

Haptocorrin (R-binder, transcobalamin I, TCN1) is a 60–70 kDa salivary glycoprotein that binds vitamin B12, protects it from stomach acid, and carries 70–80% of circulating B12 to the liver.

Haptocorrin deficiency

Haptocorrin deficiency (transcobalamin I deficiency, TCI deficiency, OMIM 193090) is a rare benign autosomal recessive cobalamin transport disorder causing low serum B12 with normal MMA, homocysteine, and no symptoms.

Haptoglobin

Haptoglobin (Hp), also called haptoglobin-hemoglobin binder, is a liver-produced acute-phase plasma glycoprotein that binds free hemoglobin for CD163-mediated macrophage clearance; depleted levels mark hemolysis, and three phenotypes (Hp1-1, Hp2-1, Hp2-2) exist.