CARTA Glossary

Displaying 301 - 400 of 799 defined words
Word Definition Related Vocabulary
Genome

The totality of DNA in a cell. Also refers to the DNA sequence that typifies an individual or species.

Genome Wide Association Study (GWAS)

An approach for “gene mapping” in which hundreds of thousands of SNPs are tested statistically for genetic associations with a phenotype.

Genomic Imprinting

Modification of the genome at the level of DNA (e.g. methylation) or its packaging into chromatin (histone tail modification via phosphorylation, acetylation, ubiquitination or glycosylation).

Genomics

The study of genome structure/function.

Genotype

The two alleles at one or more diploid loci.

Genotyping

Characterizing genetic variants at one or more loci.

Genus

A taxonomic rank used in biological classification of living and fossil organisms to group closely related species. In binomial nomenclature, the genus name plus species name forms the binomial species name (e.g. Homo sapiens).

Germinal Zone A region where cell division and proliferation occurs during vertebrate central nervous system development consisting of 2 layers lining the ventricles (ventricular zone and subventricular zone).
Glia (aka Neuroglia)

Non-neuronal cells in the central nervous system and the peripheral nervous system that do not produce electrical impulses. Their function is to ensure homeostasis, form myelin, and provide support and protection for neurons. Glia make up ~50% of our brain cells.

Global Neuronal Workspace (GNW)

A hypothesis that offers a simple connectomic scheme based upon the contribution of neurons with long-range axons to conscious processing. Their reciprocal interactions contribute to the formation of a global workspace, broadcasting signals from the sensory periphery to the whole brain, thus yielding “conscious” experience. The GNW hypothesis privileges cortical pyramidal cells with long-range excitatory axons, particularly dense in prefrontal, temporoparietal, and cingulate regions, that, together with the relevant thalamocortical loops, reciprocally interconnect multiple specialized, automatic, and non-conscious processors. Another important feature of this hypothesis is that the GNW activates in a non-linear manner, called ‘‘ignition,’’ upon access to conscious processing. Ignition is characterized by the sudden, coherent, and exclusive activation of a subset of workspace neurons coding for the current conscious content, with the remainder of the workspace neurons being inhibited.

Glucocorticoids

A class of corticosteroids that are involved in stress response and are also a part of the feedback mechanism in the immune system. E.g., Dexamethasone (a synthetic glucorticoid).

Glycans

One of the four classes of major biomolecules. Glycans consist of varying numbers of sugars (monosaccharides) attached to proteins or lipids or secreted as free glycans. Glycans are essential biomolecules whose functions can be divided into three broad categories: structural and modulatory properties (including nutrient storage and sequestration), specific recognition by other molecules, and molecular mimicry of host glycans.

Glycolipid

A type of a lipid (fat) with an attached glycan that functions to maintain the stability of the cell membrane and to facilitate cellular recognition. Glycolipids are crucial in immune response and tissue formation.

Glycoprotein

A class of proteins with covalently attached glycans. Glycoproteins play a part in important cellular functions like embryonic development, cell-to-cell recognition, cell adhesion, and immune functions.

Glycosyltransferases

Proteins with enzymatic functions that are involved in adding monosaccharides to other molecules.

Gram-Negative and Gram-Positive Staining

A characterization of bacteria based on how they differentially react with a chemical stain (crystal violet) based on their cell wall constituents.

Grandmother Hypothesis

An explanation of the post- menopausal life stage of human females whereby the existence of grandmothers serves as a biological and social adaptive advantage for humans. Post-reproductive life stages are non-existent among non-human primates, so it is hypothesized that humans evolved to have grandmothers and grandmothering to have individuals who are free to invest their energy into the offspring of their children. This off-loads the reproductive cost of parenting through social kin-networking, and off-set the resource cost of brain- building as parents are freed to provision resources. Increased resource procurement may reduce the inter-birth interval by allowing for earlier weening, which in turn increases offspring production potential, passes down generational knowledge, and increase social networks. In doing so, the grandmother ensures the survival of her genes in subsequent generations. The extended post-reproduction lifestage of grandmothers likely had the added output of producing grandfathers, who also provide benefits to the extended family, as well as their own extended reproductive timeline that competes with subsequent generations.

Gray Matter (Brain)

A major component of the central nervous system that includes regions of the brain involved in muscle control, sensory perception such as seeing and hearing, memory, emotions, speech, decision making, and self-control. Gray matter development peaks the third decade in humans.

Guillain–Barré Syndrome (GBS)

A rapid-onset muscle weakness caused by an autoimmune response in which the body’s immune system mistakenly attacks and damages the peripheral nervous system. Initial symptoms typically begin in the feet and hands with changes in sensation, pain, and muscle weakness, which then spreads to the arms and upper body of both sides. Sometimes this immune dysfunction is triggered by an infection or, less commonly by surgery, and rarely by vaccination.

Gyrification

The process of forming the characteristic folds of the cerebral cortex.  The peak of such a fold is called a gyrus (plural: gyri), and its trough is called a sulcus (plural: sulci).

Gyrus (Brain)

A ridge on the cerebral cortex that, along with surrounding sulci (furrows) creates the folded appearance of the brain in humans and other mammals.

Hadza (Hadzabe)

An indigenous ethnic group of traditionally nomadic hunter-gatherers from the central Rift Valley and Serengeti Plateau of Tanzania. Tourism, encroachment by pastoralists, and land rights disputes critically threaten their way of life.

Handaxe

A prehistoric stone tool with two faces and is usually made from flint, basalt, sandstone, quartzite, or chert.

Haplogroup

A set of similar haplotypes that share a common ancestor.

Haploid

One set of unpaired chromosomes.

Haplotype

A set of alleles along neighboring positions on a chromosome that are inherited together.

HapMap collection

A map of informative subsets of single nucleotide polymorphisms (SNPs) found along a stretch of a chromosome used to identify blocks of genetic variation existing along human chromosomes.

Health Disparity

Differences in the burden of disease, injury, violence, and health care as experienced by socially disadvantaged populations.

Hematopoietic stem cells

Stem cells that can become different types of blood cells.

Hemideletion

One of two paired chromosomes is affected by a deletion. The other chromosome is intact. 

Hemoglobin

A protein complex within red blood cells (RBCs) that binds to oxygen molecules in the lungs for delivery to tissues throughout the body. The same complex also binds carbon dioxide (CO2) and carries it back to the lungs.

Hemoglobin S

The abnormal hemoglobin protein in red blood cells (RBCs) that causes RBCs to assume a sickle, or crescent shape.

Hemoglobin Subunit Beta Gene (HBB)

A gene that provides instructions for making beta-globin, a protein component of hemoglobin. Sickle Cell Anemia is a disorder caused by a mutation in the HBB gene.

Herd Immunity

Sometimes also called “herd protection” or “indirect immunity,” this is when most of a population is immune to a specific contagious disease, which slows its spread to others that are not immune. However, because the level needed to reach this kind of immunity is so high (about 80-90% of the population), it invariably means that a lot of individuals must be infected (and often can die) before herd immunity can be achieved.

Heritability

A statistic used in the fields of breeding and genetics that estimates the degree of variation in a phenotypic trait in a population that is due to genetic variation between individuals in that population.

Heterochromatin

Tightly wrapped and inactive chromatin.

Heterozygotes

Have two different alleles at a locus.

Hind limb

The back limbs and feet of a quadrupedal animal (also, the lower limbs/legs of a human).

Hindgut fermentation

A digestive process in which cellulose and other polysaccharides are broken down by symbiotic bacteria residing the colon of some mammalian species.

Hippocampus (Brain)

A part of the limbic system that plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation. Humans and other vertebrates have two hippocampi, one in each side of the brain. It is named after its resemblance to the shape of a sea horse (hippocampus in Latin).

Histo-blood groups

Meaning “tissue-related”, these blood group antigens originally evolved on epithelial cells prior to expression on erythrocytes (red blood cells). ABO is a classic example of a histo-blood group.

Histone Deacetylase Inhibitor (HDACi)

A drug that inhibits histone deacetylases or molecules involved in modifying histone proteins. Histone deacetylases typically function to reduce chromatin accessibility and gene expression. Therefore, administration of this drug allows for higher levels of gene expression.

Histone Modification

A covalent post-translational modification (PTM) to histone proteins which includes methylation, phosphorylation, acetylation, ubiquitylation, and sumoylation. The PTMs made to histones can impact gene expression by altering chromatin structure or recruiting histone modifiers. 

Histones

Chief protein components of chromatin and can be chemically modified as part of epigenetics.

Holocene

The current geological epoch, from about 11.7 kya to the present.

Homeostasis

The state of steady internal, physical, and chemical conditions maintained by living organisms.

Hominid

A classification comprising all living and extinct “Great Apes” and humans.

Hominin

A classification of species comprising humans and our extinct relatives following the split with the common ancestor with chimpanzees.

Homo

The genus that comprises the species Homo sapiens, as well as several extinct species classified as ancestral to, or closely related to, humans.

Homo erectus

An extinct hominin species with fossil evidence from at least 1.9 million years to 70 thousand years ago and found from Africa to Indonesia. May have been the first hominin to leave Africa. H. erectus DNA may be retrievable from other species due to archaic admixture.

Homo habilis

An extinct archaic species of the genus Homo dating to ~2.1 to 1.5 mya. H. habilis means “handy man” and was named so because of its association with stone tools.  H. habilis has intermediate morphology between Australopithecus and Homo erectus. There is ongoing debate if H. habilis should be moved to the Australopithecus genus.  Initial discovery was made by Mary and Louis Leakey at Olduvai Gorge in Tanzania between 1962 and 1964.

Homo naledi

An extinct hominin species whose fossil evidence dates to 335-236 kya. An assemblage of 15 H. naledi skeletons were first found in the Dinaledi Chamber of the Rising Star cave system in 2013 (since then, a second chamber has been found with H. naledi skeletons). The fossils possess a mix of “archaic” traits similar to genus Australopithecus (e.g. cranial and pelvic morphology) and “modern” traits characteristic of genus Homo (e.g. hand morphology). H. naledi lived contemporaneously with anatomically modern humans, Neanderthals, and Denisovans but is not likely a direct ancestors of humans living today.

Homo sapiens

The hominin species comprising all living humans. Meaning “wise man” in Latin, the name was introduced by Carl Linnaeus in 1758. The earliest fossil evidence of Homo sapiens appears in Africa around 300 kya (see Jebel Irhoud Hominins).

Homology

Similarity in DNA or phenotype because of shared evolutionary history from a common ancestor.

Homoplasy

Similarity in DNA sequence or phenotype that has evolved independently.

Homozygotes

Have two identical alleles at a locus

Hormone

A signaling molecule in multicellular organisms that contributes to the regulation of physiology and behavior.

Host

A living organism on or in which a parasite, pathogen, commensal or symbiont lives (see Parasitism).

Howiesons Poort

A lithic technology cultural period in the Middle Stone Age in Africa named after the Howieson’s Poort Shelter archeological site near Grahamstown, South Africa. Dates range from ~65.8 kya to 59.5 kya. Examples include composite weapons hafted with ochre and gum compound glue and microlith blades, bone arrows, and needles.

Human Accelerated Regions (HARs)

A set of 49 segments of the human genome that are conserved throughout vertebrate evolution but are strikingly different in humans. They are named according to their degree of difference between humans and chimpanzees. Some of these highly mutated areas may contribute to human-specific traits while others may represent “loss of function” mutations, possibly due to the action of biased gene conversion rather than adaptive evolution.

Human Arcuate Fasciculus

The specialized connections composed of axons linking Broca’s area and Wernicke’s area in the human brain and is a major anatomic feature supporting language function in humans.

Hunter-gatherer

A human living in a society in which most or all food is obtained by foraging (collecting wild plants and pursuing wild animals), in contrast to agricultural societies, which rely mainly on domesticated species.

Hunting hypothesis

The idea that hunting of large game by males provided sufficient provisions for themselves, their mates and offspring, while allowing for the reduction of female workloads, enhancement of fertility, and favoring of the later ages at maturity needed to learn and perfect essential skills. But modern data show that large animal prey would not have provided the reliable energy stream the argument requires.

Hybridization

Breeding among recognized species.

Hydroxylase

An enzyme involved in the first step of aerobic oxidation of organic compounds.

Hygiene Hypothesis

A lack of early childhood exposure to infectious agents, symbiotic microorganisms and parasites believed to increase susceptibility to allergies and autoimmune diseases.

Hyperalgesia

Increased sensitivity to pain.

Hyperkatifeia

Pain, hypohedonia, dysphoria, anxiety, hyperalgesia, irritability, and sleep disturbances associated with drug abstinence following excessive drug taking.

Hypocretin (Orexin)

A neuropeptide that regulates arousal, wakefulness, and appetite.

Hypohedonia

A diminished capacity for pleasure.

Hypoxia

A condition characterized by less than the normal amount of oxygen reaching the tissues; also, low partial pressure of oxygen at high elevations (hypobaric hypoxia).

I-type lectins

A class of lectins belonging to the immunoglobulin superfamily. e.g., Siglecs

Icon

A sign that shares perceived physical properties with the thing it refers to (its “referent”) (Kluender, 2020).

Idiosyncrasy

A mode of behavior or way of thought peculiar to an individual.

Imitation

Behavior copying. This term has been used to mean everything from social learning in general to the reproduction of action intentions but is now most commonly used in the narrow sense of copying the form or topography of observed movements.

Immediate Return Hunter-Gatherers

Those who do not store food, but consume it within a day or two of obtaining it. This means there is no opportunity to accumulate surplus.

Immune Cells

Cells that are part of the immune system. Most develop from stem cells in the bone marrow and become different types of white blood cells (the microglia of the brain originate in the yolk sack during embryonic development). Immune cells are broadly classified into innate and adaptive immune cells. Innate immune cells include neutrophils, basophils, mast cells, monocytes and eosinophils, dendritic cells, and macrophages. Adaptive immune cells include B-cells and T-cells. T-Cells and Natural Killer T-cells mediate important dialogues between innate (rapid) and adaptive (slower) immune responses. B-cells and T-cells can form long- term immunological memory.

Immune system

The biological defense system of an organism that protects against disease.

Immunity

The capability of multicellular organisms to resist harmful microorganisms from entering it and compromising its biological systems. The balanced state of adequate biological defenses to fight infection, disease, or other unwanted biological invasion, while having adequate tolerance to avoid allergy, and autoimmune diseases. It critically relies on recognition of both self and non-self.

Immunoglobulin domain/fold (Ig)

A type of region (domain) present in many different proteins that is self-stabilizing and folds independently.

Immunoglobulins

A type of protein that forms antibodies and other receptors both on cell surfaces and as soluble proteins of vertebrates. Comprised of a massive superfamily, immunoglobulins perform many different functions, including recognition, binding, or adhesion processes of cells.

Immunology

The branch of biology and biomedicine concerned with the study of immune systems.

Immunoreceptor tyrosine-based activation motif (ITAM)

A highly conserved region in the cytoplasmic domain of signaling chains of adapter proteins and receptors and typically result in activation of inflammatory responses.

Immunoreceptor tyrosine-based inhibitory motif (ITIM)

A conserved sequence of amino acids, including phosphorylated tyrosine, that is found intracellularly in the cytoplasmic domains of many inhibitory receptors.

IncRNA

Long non-coding microRNA

Indel

An insertion or deletion of a DNA sequence.

Index

A sign that depends for its reference on the physical presence of the thing that it refers (its “referent”) to at some point in space and time (e.g. smoke, a weather vane, a bullet hole, your index finger) (Kluender, 2020).

Induced Pluripotent Stem Cells (iPSC)

Somatic (body) cells that are artificially reprogrammed to an embryonic-like stem cell state and differentiated into other types of cells.

Infection

The invasion of an organism’s organs or tissues by pathogens, their multiplication, and the reaction of the host tissues to the pathogens.

Infectious (disease)

The capability of producing infection or spreading disease to others. Synonymous with communicable and transmissible.

Inferior Frontal Gyrus (Brain)

The lowest positioned gyrus of the frontal gyri, of the frontal lobe, and is part of the prefrontal cortex. It is located in Broca’s area, which is involved in language processing and speech production.

Inferior Temporal Cortex (Brain)

The cerebral cortex on the inferior convexity of the temporal lobe in primates, including humans and is It is crucial for visual object recognition.

Inflammation

An often-painful localized redness, swelling, and heat that is the body’s response to an injury or infection. While uncomfortable, it indicates that your body is working hard to repair itself or to defend against infection.

Influenza

Often referred to as “flu,” this is a highly contagious viral respiratory illness. Symptoms include fever, severe body aches, and catarrh. Because it is so contagious, influenza often produces epidemics. There are several influenza viruses that affect humans (A, B, C).

Inhibitory neurotransmitter

A chemical messenger that decreases the likelihood that the neuron will fire an electrical signal called an action potential (see also excitatory neurotransmitter).

Intentionality

The power of minds to be about, to represent, or to stand for, things, properties and states of affairs. Refers to the ability of the mind to form representations and should not be confused with intention. Beliefs about others’ beliefs display what is sometimes known as “higher-order intentionality.”

Inter-birth-interval

The space between births.

Interactive synchrony

Temporal coordination of behavior, physiology, neural activity, and/or mental representations between individuals.

Internal model

A simulation of a system’s response to events or states. In motor control, forward models use motor commands to predict sensory consequences whereas inverse models use intended sensory consequences to generate appropriate motor commands.

Intersectional neuroscience framework

A research framework that adapts procedures to be more inclusive of underrepresented groups through community engagement with diverse participants and individualized methods to accommodate neural diversity.

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