Z_2_11 — Genetics of Immunity and MHC Diversity

The major histocompatibility complex (MHC) — known as the human leukocyte antigen (HLA) system in humans — is the most polymorphic gene region in the human genome, encoding cell-surface glycoproteins essential for adapti

Z_2_00 — Medical Genetics Health: Subfolder Summary

Z_2_07 — Genetics of Disease Resistance

Infectious disease has been the most powerful selective force shaping the human genome, leaving signatures across thousands of loci. The best-understood example is sickle cell disease (HbS, Glu6Val in HBB): heterozygous

Z_2_23 — Immune System & Immunology

The immune system is a multi-layered defense network that protects organisms against pathogens including bacteria, viruses, fungi, and parasites. It comprises two interconnected arms: innate immunity, which provides rapi

Z_2_01 — HLA System & Archaic Immune Inheritance

The Human Leukocyte Antigen (HLA) system is the most polymorphic region of the human genome, encoding cell-surface proteins critical to adaptive immune function. Located on chromosome 6p21.3, the Major Histocompatibility

Z_1_06 — Sex Determination Genetics

Sex determination — the biological process that establishes whether an organism develops as male, female, or an alternative reproductive type — employs remarkably diverse mechanisms across the tree of life. In placental

Z_1_17 — Environmental Epigenetics & Toxicogenomics

Environmental epigenetics examines how chemical exposures, nutritional states, and ecological stressors modify gene expression without altering DNA sequence — through DNA methylation, histone modifications, and non-codin

Z_1_18 — Junk DNA & the ENCODE Controversy: Function, Noise, and the Human Genome

The term "junk DNA" — coined by Susumu Ohno (1972) to describe non-coding DNA sequences in eukaryotic genomes that appeared to have no functional role — ignited one of the most contentious debates in modern genomics: how

Z_1_05 — Genomic Imprinting and Parent-of-Origin Effects

Genomic imprinting is an epigenetic phenomenon in which a gene's expression depends on whether it was inherited from the mother or the father — violating the standard Mendelian assumption that both parental copies functi

Z_1_03 — Human Genome Project and Its Legacy

The Human Genome Project (HGP), launched in 1990 and completed in 2003, was the largest coordinated biological research effort in history — a $3 billion, 13-year international collaboration to sequence all ~3.2 billion b

Z_1_00 — Genome Structure Organization: Subfolder Summary

Z_1_10 — Chromosome Evolution and Karyotype

Karyotype — the number, size, and morphology of chromosomes in a cell — varies enormously across species, from n=1 in the ant Myrmecia pilosula to n=630 in the fern Ophioglossum reticulatum. Humans have 2n=46 (23 pairs),

Z_1_12 — Genome Architecture and 3D Organization

The human genome — approximately 6.4 billion base pairs of DNA — is packed into a nucleus only ~6 μm in diameter. If stretched end-to-end, the DNA of a single human cell would extend about 2 meters, yet it is packaged an

Z_1_11 — Polyploidy and Genome Duplication

Polyploidy — the possession of more than two complete sets of chromosomes — is a major force in genome evolution, particularly in plants and some animal lineages. Susumu Ohno (1970) proposed that whole genome duplication

Z_4_00 — RNA Protein Cell Biology: Subfolder Summary

Z_4_02 — Stem Cells and Pluripotency

Stem cells — defined by the dual capacity for self-renewal (division producing at least one daughter cell retaining stemness) and differentiation (specialization into distinct cell types) — are the foundational building

Z_4_23 — Memory as Physical and Molecular Phenomenon

What is a memory made of? The question has driven neuroscience from Santiago Ramón y Cajal's 1894 hypothesis that learning strengthens connections between neurons, through Donald Hebb's 1949 postulate that "neurons that

Z_4_03 — Forensic Genetics and DNA Identification

Forensic genetics uses DNA analysis to identify individuals, establish biological relationships, and solve criminal cases — a revolution that began when Sir Alec Jeffreys (1984, University of Leicester) discovered DNA fi

Z_4_14 — RNA Interference: Gene Silencing by Small RNAs

RNA interference (RNAi) — the process by which small double-stranded RNA molecules silence gene expression by targeting complementary messenger RNA (mRNA) for degradation or translational repression — is one of the most

Z_0_00 — Molecular Biology & Genomics: Section Summary