RESEARCH BASE
Search 3,721 documents across 34 fields — every claim tier-rated by evidence
3,633 are the core, quality-scored corpus (34 lettered sections — see How We Work); the remaining 88 are cross-corpus synthesis documents (68 InterDocs, 12 Connections, 8 Theories) also indexed here.
3,721 results for "N" — page 115 of 187
L_3_16 — Genomic Imprinting & Evolutionary Conflict
Genomic imprinting — the epigenetic phenomenon in which a subset of genes (~100–200 in mammals) are expressed from only one parental allele, with the other allele silenced by DNA methylation and histone modification esta
L_3_06 — Genetics of Intelligence and Cognition
The genetics of intelligence — one of the most studied yet contentious areas in behavioral genetics — has established that cognitive ability, as measured by standardized tests, has a substantial heritable component (~50–
L_3_17 — Endogenous Retroviruses (HERVs) in the Human Genome
Human endogenous retroviruses (HERVs) — remnants of ancient retroviral infections that integrated into the germline DNA of human ancestors and have been vertically transmitted through the host genome for millions of year
L_3_09 — HLA Diversity and Immune System Evolution
The Human Leukocyte Antigen (HLA) system — the human version of the Major Histocompatibility Complex (MHC) found in all jawed vertebrates — is the most polymorphic gene region in the entire human genome. Located on chrom
L_3_14 — Genetic Bottleneck Recovery and Founder Effects
A genetic bottleneck occurs when a population's size is drastically reduced, causing a random loss of genetic variation (alleles) that cannot be recovered through subsequent population growth. Founder effects are a speci
L_3_04 — Y-Chromosome Phylogeny and Patrilineal Deep History
The Y chromosome, transmitted exclusively from father to son, provides a uniquely informative window into patrilineal human history.
L_3_13 — Human Accelerated Regions: What Makes Us Genetically Unique
Human Accelerated Regions (HARs) are short segments of the genome that were highly conserved across millions of years of mammalian evolution — indicating strong functional constraint — but then underwent a burst of rapid
L_3_05 — Blood Type Genetics and the ABO System
Blood group genetics represents one of the earliest and most clinically important applications of Mendelian inheritance in human biology. Karl Landsteiner's discovery of the ABO blood group system (1900–1901) — which ear
L_3_10 — Telomeres Aging and Longevity Genetics
Telomeres — the repetitive DNA sequences (TTAGGG in vertebrates) capping the ends of linear chromosomes — protect genome integrity by preventing chromosome ends from being recognized as double-strand breaks and triggerin
L_3_11 — Genetics of Taste and Dietary Adaptation
Taste perception — the ability to detect sweet, salty, sour, bitter, and umami (savory) stimuli — is mediated by genetically encoded receptor proteins whose variation across individuals and populations reflects evolution
L_3_18 — Horizontal Gene Transfer in Eukaryotes
Horizontal gene transfer (HGT) — the movement of genetic material between organisms through mechanisms other than vertical parent-to-offspring inheritance — was long considered a predominantly prokaryotic phenomenon, cen
L_3_12 — Genetics of Pigmentation: Skin, Hair, and Eye Color Evolution
Human pigmentation — the variation in skin, hair, and eye color across populations — is one of the most visible and best-understood examples of natural selection in our species. Pigmentation is determined primarily by th
L_3_03 — Lactase Persistence and Gene-Culture Coevolution
Lactase persistence — the ability of adults to digest the milk sugar lactose — is the most thoroughly documented case of gene-culture coevolution in the human species. The ancestral mammalian condition is lactase non-per
L_3_02 — Caduceus / Twin-Serpent / DNA Symbolism
This document surveys the widespread twin-serpent-on-axis motif and compares it with the modern DNA double helix. The iconography itself is real and historically well documented, and the molecular structure of DNA is lik
L_3_08 — Genetics of Skin, Hair, and Eye Color
Human pigmentation — skin, hair, and eye color — is one of the best-understood complex traits in human genetics, with a relatively modest number of genes explaining a large proportion of variation compared to most polyge
L_3_07 — Behavioral Genetics: Nature and Nurture
Behavioral genetics — the scientific study of how genetic and environmental factors contribute to individual differences in behavior — has transformed our understanding of human psychology over the past half-century. Thr
L_5_10 — Neandertal Introgression: Which Genes and Why They Persisted
When modern humans (Homo sapiens) migrated out of Africa ~60,000-70,000 years ago and encountered Neanderthals (Homo neanderthalensis) in western Asia and Europe, the two species interbred — and the genetic legacy of tha
L_5_15 — Genetic Genealogy: DNA Ancestry Testing and Population History
Genetic genealogy — the use of DNA testing to determine relationships and ancestry — has revolutionized both personal genealogy and population genetics since the early 2000s. Three types of DNA analysis provide different
L_5_05 — Epigenetic Clocks: Measuring Biological Age
Epigenetic clocks are mathematical models that estimate biological age — the physiological age of an organism's cells and tissues — based on DNA methylation patterns at specific CpG sites (regions where a cytosine nucleo
L_5_03 — Pharmacogenomics and Ancestral Medicine
Pharmacogenomics — the study of how genetic variation influences individual responses to drugs — bridges genetics, pharmacology, and clinical medicine. Humans carry extensive polymorphism in genes encoding drug-metaboliz
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