All articles starting with H
20,046 articles
Homologous chromosome
Homologous chromosome: one of a matching pair of chromosomes, one maternal and one paternal, that pair and recombine during meiosis; basis of the Sutton-Boveri chromosome theory and genetic mapping.
Homologous recombination
Homologous recombination, also called recombination repair, is a DNA repair pathway that uses a homologous template, usually a sister chromatid, to accurately repair double-strand breaks.
Homologous series
A homologous series is a family of organic compounds sharing a functional group and general formula, each member differing from the next by one CH2 unit.
Homology (biology)
Homology (biology): similarity of a gene, structure, or behavior in two organisms because a common ancestor possessed it; contrasted with homoplasy and analogy, tested by character congruence.
Homology (mathematics)
Homology is a construction in algebraic topology that assigns to each topological space homology groups recording, dimension by dimension, cycles such as loops and voids that are not boundaries.
Homology Directed Repair
Homology directed repair (HDR) is a DNA double-strand break repair family, spanning error-free homologous recombination, error-prone single strand annealing, and MMEJ, that uses homologous templates and underlies precise CRISPR gene editing.
Homology Medicines
Homology Medicines was a genetic medicines company founded in 2015 to develop gene therapy and nuclease-free gene editing for rare diseases using proprietary AAV vectors.
Homology modeling
Homology modeling, also called comparative modeling, is a computational method that predicts a protein's 3D structure using homologous proteins with known structures as templates, with accuracy depending on sequence identity.
Homomonument
Homomonument: world's first free-standing gay memorial, Amsterdam Westermarkt, unveiled 5 September 1987, designed by Karin Daan; three pink granite triangles symbolizing past, present and future.
Homomorphic encryption
Homomorphic encryption, or privacy homomorphism, is encryption that permits computation directly on encrypted data without the secret key; Craig Gentry's 2009 lattice-based scheme made it practical.
Homomorphism
A homomorphism is a map between two algebraic structures of the same kind, such as groups or rings, that preserves their operations, making it algebra's basic tool for comparing structures.
Homomya
Homomya (Agassiz) is a fossil marine bivalve genus in the family Pholadomyidae, order Pholadomyida, ranging from Early Triassic to middle Eocene, with infaunal suspension-feeding species in Jurassic and Cretaceous strata of Europe, Asia, and Texas.
Homonym
Homonym: a word sharing spelling or pronunciation with another word but differing in meaning. Covers homophones (same sound), homographs (same spelling), etymology from Greek homos and onoma, and the homonymy-versus-polysemy distinction in linguistics.
Homonymous hemianopsia
Homonymous hemianopsia (homonymous hemianopia): loss of the same half of the visual field in both eyes from retrochiasmal lesions (optic tract, LGN, radiations, occipital cortex), usually stroke; macular sparing localizes to occipital cortex.
Homophily
Homophily is the tendency of individuals to form social ties with similar others, defined by Lazarsfeld and Merton in 1954 and structuring marriage, friendship, and work ties.
Homophobia
Homophobia is prejudice, fear, or hostility toward lesbian, gay, and bisexual people, coined by George Weinberg and popularized in his 1972 book; distinguished from heterosexism and linked to measurable LGBTQ+ health harms.
Homophone
Homophone: words pronounced identically but differing in meaning, from Greek homos 'same' plus phone 'sound'; may share spelling (bark) or not (bare/bear); distinct from homograph and polysemy.
Homopolar generator
The homopolar generator, also known as the Faraday disk, is a direct-current generator with a conductive disk spinning in a magnetic field, invented by Michael Faraday in 1831.
Homopolar motor
A homopolar motor is a direct-current electric motor whose fixed magnetic polarity needs no commutator; Faraday first demonstrated one in 1821 at the Royal Institution in London.
Homorod
Homorod is the name of several related places in Transylvania, Romania, including a commune in Brașov county, a village in Hunedoara county, and a tributary of the Olt River.
Homoserine
Homoserine, or L-homoserine, is a four-carbon amino acid central to bacterial and plant pathways. It is a platform chemical and precursor to signaling molecules used for quorum sensing.
Homoserine dehydrogenase
Homoserine dehydrogenase (EC 1.1.1.3, hom gene) reduces aspartate semialdehyde to homoserine, the committed step toward threonine, methionine, and isoleucine; regulated by threonine feedback, engineered for amino acid production.
Homoserine kinase
Homoserine kinase (HSK, EC 2.7.1.39, thrB) phosphorylates L-homoserine to O-phospho-L-homoserine in threonine biosynthesis; a GHMP kinase whose 2000 Methanocaldococcus jannaschii structure revealed base-free, transition-state-stabilized catalysis.
Homoserine/serine acetyltransferase MetX-like
MetX-like (IPR008220) homoserine/serine acetyltransferases, EC 2.3.1.31, acylate L-homoserine with acetyl-CoA as the committed step of methionine biosynthesis; non-homologous to MetA, Ser-Asp-His triad, druggable in M. tuberculosis.
Homosexual behavior in animals
Homosexual behavior in animals, also called homosexuality in animals or same-sex sexual behavior, is sexual activity between same-sex animals, documented in over 1,500 species including mammals, birds, and insects.
Homosexuality
Homosexuality, also called same-sex sexuality, is sexual, romantic, or emotional attraction or activity between members of the same sex, known as being gay or lesbian.
Homosexuality and psychology
Homosexuality and psychology covers how psychology and psychiatry moved from classifying same-sex orientation as a DSM and ICD mental disorder (removed 1973 and 1990) to minority stress and affirmative care frameworks, and the evidence against conversion therapy.
Homosexuality and the Anglican Communion
Homosexuality and the Anglican Communion covers the dispute over same-sex relationships, from Lambeth I.10 (1998) and Gene Robinson (2003) through GAFCON, the Church of England's 2023 Prayers of Love and Faith, and the 2025 Global Anglican Communion schism.
Homosexuality in American football
Homosexuality in American football: 16 gay or bi NFL players have come out, from Dave Kopay (1975) to Carl Nassib, the first active player (2021) and only one to play a regular-season down; Michael Sam was the first drafted (2014).
Homosexuality in ancient Greece
Same-gender love and sexual activity in ancient Greece, chiefly pederasty between an erastes and eromenos, plus peer, adult-male, and female relations; governed by active/passive status norms, attested from lyric poetry and Sappho, and debated by Dover, Foucault, and later scholars.