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 "System A" — page 122 of 187
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_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_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
L_5_16 — Archaeogenetics: Ancient DNA and the Human Past
Archaeogenetics — the extraction and analysis of DNA from ancient human, animal, and plant remains — has transformed our understanding of human history since the field's breakthrough in 2010. Advances in next-generation
L_5_01 — Human Microbiome and Co-Evolution
The human microbiome — the aggregate community of microorganisms (bacteria, archaea, fungi, viruses, protists) living on and within the human body — comprises roughly 38 trillion microbial cells (Sender et al., 2016, Cel
L_5_06 — Genetic Adaptation to Disease: Malaria, Plague, TB
Infectious disease has been the most powerful selective force on the human genome throughout history. Pathogens — particularly malaria, plague, tuberculosis, smallpox, and cholera — have killed more humans than all other
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