CARTA Glossary

A research approach in which genetic variants from extinct archaic human relatives (e.g., Neanderthals and Denisovans) are introduced into modern human cells to study how those ancient genes function and how they impact the function of those cells.

In invertebrates, a long, slender projection of a neuron that transmits information (as electrical impulses) to different neurons, muscles, and glands.

Subcortical nuclei in the base of the forebrains of vertebrates, including humans, which are involved with a variety of functions, such as control of voluntary motor movements, procedural learning, and routine behaviors or “habits” (e.g., teeth grinding, eye movements, cognition, and emotion).

A term used in paleoecology or forensic botany to describe the age of a site or specimen based on the growth rings of woody plants (dendrochronology) or the successional stage of local flora.

An artificially grown in vitro brain model used for investigating brain development and neurological disease. Brain organoids are clusters of brain-like cells that are derived from induced pluripotent stem cells and embryonic stem cells.

The majority of the nervous system that consists of the brain, spinal cord, retina, optic nerves, and olfactory epithelium. The CNS integrates sensory information and coordinates and influences the activity of the body in bilaterally symmetric animals (all multicellular animals except sponges and radially symmetric animals such as jellyfish).

The outer layer of the cerebrum, composed of folded gray matter, and plays an important role in consciousness.

A complex of DNA and proteins (histone and adaptor proteins) forming chromosomes.

A sequence of three nucleotides along a DNA or RNA chain encoding a single amino acid, and start or stop.

The linguistic ability to combine words into hierarchical structures, including the use of recursion, subordination, and long-distance dependencies to express intricate relationships. See syntax.

Behavior and norms that are shared, learned, and socially transmitted.

An extinct hominin population contemporary with Neanderthals that hybridized with ancient humans and Neanderthals. Knowledge of Denisovan morphology is limited to two small fossils found in Siberia, a jaw in Tibet, a skull in China, and a mandible in Taiwan.

The specific order of the nucleotide bases along a strand of DNA.

The inner cell mass of the human blastocyst, the rapidly dividing fertilized egg at four to seven days post fertilization. ESCs are pluripotent, meaning they can differentiate into all cell types of the three embryonic tissue layers.

A non-coding DNA element that binds transcription factors to boost the expression of one or more target genes, regardless of its orientation or location relative to the gene.

A field of biology that compares the developmental processes of different organisms to determine their ancestral relationships and how developmental changes lead to novel evolutionary traits.

The perception and synchronization of motor movements to external periodic acoustic stimuli (often studied in the context of the evolution of music and speech).

The largest of the four major lobes of the brain in mammals, and is located at the front of each hemisphere. It is devoted to action such as skeletal movement, ocular movement, speech control, the expression of emotions. In humans, the largest part of the frontal lobe is the prefrontal cortex.

A DNA sequence which encodes a specific function.

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

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 sheaths, and provide support and protection for neurons. Glia make up ~50% of our brain cells.

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

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

Regions 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.

Since the evolutionary split between the human lineage and other great apes (6–7 million years ago), the human brain more than tripled in volume and increased in complexity. While early hominins such as Australopithecus afarensis (3.9 to 2.9 million years ago) had brain volumes of roughly 400–500 cubic centimeters, similar to modern chimpanzees, it was with the emergence of genus Homo around 2–2.5 million years ago that brain size began to increase more rapidly. Homo habilis (2.4 to 1.4 million years ago) had a cranial capacity of about 600–700 cc and Homo erectus (1.9 million years ago to 110 thousand years ago ) reached 900–1100 cc. In modern humans, average brain volume is approximately 1,300–1,400 cc. This expansion involved disproportionate growth of the cerebral cortex, particularly regions associated with language, abstract reasoning, planning, and social cognition. Changes in brain organization, connectivity, and prolonged developmental periods (including extended childhood) were also crucial. Together, these evolutionary modifications supported increasingly complex tool use, symbolic thought, culture, and social structures.

A gene that encodes a transcription factor involved in regulating cell growth, apoptosis (cell death), and DNA damage responses, and is frequently silenced or hypermethylated in various cancers.

Myelin sheath-forming glial cells that have progressed from progenitor stages but have not yet fully differentiated or begun wrapping axons with insulating myelin sheaths.

A structured system of communication that is generative (combine words/symbols to convey an infinite number of ideas), recursive (builds upon itself without limit), and has displaced reference (describe things not present).

The subfield of linguistic semantics that studies how individual words convey meaning, the relationship between those meanings, and how the lexicon is structured in the mind.

A prominent groove on the lateral surface of the occipital lobe that marks the anterior boundary of the primary visual cortex; its posterior displacement in human evolution is often cited as evidence for the expansion of parietal association areas.

Membrane-bound cell organelles that generate most of the chemical energy, adenosine triphosphate (ATP), needed to power the cell’s biochemical reactions. Mitochondria are believed to be endosymbionts that were originally prokaryotic cells that became incorporated into eukaryotic organisms.

Change in a DNA or RNA sequence.

An extinct Eurasian hominin species that existed from 500-30 kya and interbred with ancient humans and Denisovans.

A bundle of fibers that transmits impulses of sensation to the brain or spinal cord, and impulses from these to the muscles and organs.

The specialized cells of the nervous system responsible for processing, transmitting, and responding to information in the form of electrical and chemical signals. They are the building blocks of the brain, spinal chord, and peripheral nerves.

A gene that encodes an RNA-binding protein primarily involved in regulating alternative splicing in neurons. NOVA1 is involved in early brain development and is implicated in autism and schizophrenia. Archaic variants of NOVA1 archealized into human brain organoids affect alternative splicing, synaptic protein interactions, and neural connectivity.

The complex process by which the nervous system is formed, organized, and matured, spanning from early embryonic neurulation to the refinement of neural circuits through adulthood.

A cellular quality-control mechanism in eukaryotic cells that identifies mRNAs with premature stop codons and selectively degrades them to maintain protein integrity and prevent cellular dysfunction.

Molecular building blocks for DNA and RNA Specifically, they consist of three components: a 5-carbon sugar, a phosphate group, and a nitrogenous base. The type of sugar, either deoxyribose or ribose, determines if the resulting nucleic acid is DNA or RNA.

A neural structure of the vertebrate forebrain involved in sense of smell.

High-order cortical regions located at the junction of the parietal and occipital lobes that integrate multisensory information, particularly relating to spatial awareness, visual attention, and navigation.

The cerebral cortex that covers the front part of the frontal lobe and is linked to complex cognitive behavior, personality, long and short-term memory, decision making, speech, language, and a person’s will to live.

Regions of the cerebral cortex responsible for processing sensorimotor control, and is composed of the primary somatosensory cortical area (SI) and the primary motor cortical area (MI). These areas manage sensory and motor functions related to the trunk, limbs, and orofacial regions.

Located in the posterior pole of the occipital lobe, it is the first cortical area to receive and process visual information from the lateral geniculate nucleus of the thalamus.

Binding sites on chromosomes for transcription factors, which are involved in gene regulation.

The process by which the nervous system integrates sensory information (from vision, touch, proprioception, etc.) with motor commands to produce coordinated, purposeful movement.

The linear order of the nucleotide building blocks, which encodes individual form and function.

An undifferentiated cell capable of giving rise to indefinitely more cells of the same type, and from which certain other kinds of cells arise by differentiation. See embryonic stem cell (ESC) and induced pluripotent stem cell (iPSC).

A depression or groove in the cerebral cortex that, along with a gyrus (ridge), creates the folded appearance of the brain in humans and other mammals. The larger sulci are usually called fissures.