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.
2,036 results for "CT scan" — page 68 of 102
L_1_11 — Convergent Genetic Evolution — Same Solutions, Different Lineages
Convergent evolution — the independent evolution of similar features in species from different evolutionary lineages — is one of the most powerful demonstrations of natural selection's predictability and one of the deepe
L_4_05 — Paleogenomics Methods and Ancient DNA
Paleogenomics — the study of ancient genomes — has transformed archaeology, anthropology, and evolutionary biology over the past two decades, recognized by the 2022 Nobel Prize in Physiology or Medicine awarded to Svante
L_4_04 — Ancient Proteomics and Paleoproteomics
Paleoproteomics — the recovery and analysis of ancient proteins from archaeological and paleontological specimens — has emerged as a revolutionary complement to ancient DNA (aDNA), dramatically extending the temporal and
L_4_03 — Genetic Clocks and Molecular Dating
The molecular clock — the concept that DNA and protein sequences accumulate mutations at approximately regular rates over time — provides a powerful tool for dating evolutionary divergences independently of the fossil re
L_4_12 — CRISPR Gene Drives and Population Genetics Ethics
CRISPR gene drives — genetic engineering systems that combine CRISPR-Cas9 gene editing with super-Mendelian inheritance to spread a modified gene through an entire wild population far faster than natural selection — repr
L_4_10 — Sex Chromosome Evolution
Sex chromosomes — the genetic elements that determine biological sex in many organisms — represent one of the most remarkable stories in genome evolution. In mammals, the XX/XY system prevails: females have two X chromos
L_4_08 — Genetic Genealogy and Forensic Genomics
Genetic genealogy — the use of DNA testing for genealogical purposes — has undergone an explosive expansion since the early 2000s, driven by direct-to-consumer (DTC) genetic testing companies (23andMe, AncestryDNA, MyHer
L_4_15 — Y-Chromosome and mtDNA Mismatch Patterns in Human Populations
The Y chromosome (paternally inherited, non-recombining) and mitochondrial DNA (maternally inherited) provide independent genealogical records of male and female lineage histories, respectively. When these two markers te
L_0_00 — Genetics & Human Origins: Section Summary
L_2_02 — Population Genetics and Hardy-Weinberg Equilibrium
Population genetics — the mathematical study of allele frequency change in populations — provides the quantitative framework underlying evolutionary biology. The Hardy-Weinberg principle (1908), independently derived by
L_2_08 — East Asian Genetics and Population History
East Asia — comprising China, Japan, Korea, Mongolia, Taiwan, and mainland Southeast Asia — is home to the largest human population concentration on Earth and harbors a complex genetic history shaped by major north-south
L_2_16 — Genetic Diversity and Inbreeding: Population Health Across History
Genetic diversity — the total amount of genetic variation within a population — is a fundamental determinant of population health, adaptive potential, and long-term survival. The loss of diversity through inbreeding (mat
L_2_07 — European Genetics and Three Ancestral Populations
The genetic history of Europe has been revolutionized by ancient DNA, revealing that most present-day Europeans can be modeled at a broad level as mixtures of three major ancestral components assembled over the past ~10,
L_2_01 — Domestication Genetics — How Humans Reshaped Life
Domestication — the genetic transformation of wild species into human-dependent organisms — ranks among the most consequential biological processes in Earth's history.
L_2_03 — Ancient African Genetics
Africa harbors the greatest human genetic diversity on Earth — a direct consequence of being the continent of human origin, where populations have accumulated genetic variation for ~300,000+ years. Modern African populat
L_2_15 — Population Structure of the Ancient Near East: Farming Spread Genetics
The Neolithic Revolution — the independent invention of agriculture in the Fertile Crescent (~10,000-8,000 BCE) — was one of the most consequential transformations in human history, and ancient DNA has revealed that the
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_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_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
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