CARTA Glossary

A biochemical process in which an acetyl group (CH₃CO) is transferred to a molecule, typically a protein, from a donor molecule like acetyl-CoA. This modification usually occurs on the lysine residues of proteins, particularly histones, which are involved in DNA packaging. Acetylation can have significant effects on the structure and function of proteins, and it plays a critical role in regulating various biological processes, including chromatin remodeling.

The persistence of beneficial DNA variants in the modern human genome that were gained through interbreeding with now-extinct archaic species, such as Neanderthals and Denisovans.

Alternative DNA sequence at the same locus (location on the chromosome)

Organic compounds that are the building blocks of proteins and participate in a number of processes such as neurotransmitter transport and biosynthesis. Amino acids are encoded by the genome as different three nucleotide codes.

DNA that is extracted from ancient specimens (skeletons, mummified tissues, frozen specimens, archeological material, archival collections, sediments, and dirt). The current upper age limit for ancient DNA extraction and sequencing is 0.4-1.5 mya.

The proposed geologic epoch defined by human influence on the Earth. There is yet to be consensus for when the anthropocene began with suggestions ranging from the start of the agricultural revolution to the first atomic explosion.

The scientific study of complete genomes from ancient biological remains, including humans, animals, and plants, to investigate evolutionary history, population dynamics, and past environments. Archaeogenomics extends the scope of archaeogenetics by analyzing whole-genome sequencing data rather than individual genes or limited genetic markers, allowing for a more comprehensive reconstruction of ancestry, adaptation, and interactions among ancient populations.

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

One of the two species comprising the genus, Pan, having branched from chimpanzees ~1 million years ago. Sometimes referred to as “pygmy chimpanzee.” Bonobos, compared to chimpanzees, are more gracile, have female social dominance, relatively long legs, pink lips, a dark face, a “tail-tuft” through adulthood, and parted long head hair. The species is omnivorous and inhabits primary and secondary forests, including seasonally inundated swamp forests. The bonobo is found in a 500,000 km² (190,000 sq mi) area of the Congo Basin, only south of the Congo River, in the Democratic Republic of the Congo. Due to political instability, little field work in their natural habitat has been performed. Most behavioral knowledge is a result of studies of captive bonobos.

One of the two species comprising the genus, Pan, having branched from bonobos ~1 million years ago. Sometimes referred to as “common chimpanzees”. Native to sub-Saharan Africa, chimpanzees are found in and around the Congo Basin (north of the Congo River) and throughout West Africa. Chimpanzees are divided into four subspecies, based on appearance and distribution. Compared to bonobos, chimpanzees are somewhat larger, more aggressive, and exhibit male social dominance.

A discrete strand of tightly packaged chromatin.

An illness that is transmittable from an infected person or animal to another person or animal through direct contact or indirectly via contaminated food, water, or a vector.

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 and a jaw in Tibet.

A process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter, DNA methylation typically acts to repress gene transcription.

The process of artificial selection by humans for desired traits of plants, animals, fungi, and microorganisms. This implies the complete control of the reproduction of those species.

Processes that alter gene activity without changes to the underlying DNA sequence. Primary mechanisms of epigenetic regulation include DNA methylation, histone modification, and non-coding RNA. Epigenetic regulation is reversible and can be influence by environmental factors, lifestyle, and other external conditions.

An extensive belt of grassland plains stretching approximately 8,000 kilometers across Europe and Asia, from Hungary and Romania in the west to Manchuria in northeastern China. It is one of the world’s largest continuous temperate grassland ecosystems.

A DNA sequence which encodes a specific function.

Movement of alleles between populations via mating.

Change in allele frequencies, including fixation and loss, by chance.

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).

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.

The process by which sugar molecules (glycans) are added to proteins, lipids, or other organic molecules. This post-translational modification plays a crucial role in the structure, stability, and function of many biomolecules.

A set of similar haplotypes that share a common ancestor.

A well-preserved Middle Pleistocene skull dated to approximately 146,000 years ago that was discovered near Harbin City, in Heilongjiang Province, northeastern China. It is large and robust, with a combination of archaic and modern human features. In 2021, researchers proposed that the Harbin cranium represents a new species, Homo longi (“Dragon Man”), which they argued might be a close sister group to modern humans. Others have classified it within the broader Homo heidelbergensis–Denisovan spectrum, seeing it as part of the archaic human diversity in Pleistocene East Asia.

The Harbin cranium was originally found in 1933 by a Chinese laborer working on the construction of a bridge, who hid the skull in a well to prevent it from being seized by occupying Japanese forces. Knowledge of the skull and its location was kept secret for decades until the worker’s family retrieved it shortly before his death. It was donated to the Hebei GEO University in 2018.

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

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. H. erectus may have been the first hominin to leave Africa. H. erectus DNA may be retrievable from other species due to archaic admixture.

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).

People whose livelihood relies on foraging: hunting animals, fishing, and gathering wild plants and other resources for sustenance.

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

Transfer of alleles between species.

A fossilized human cranium dated to approximately 300,000–125,000 years ago, that was discovered in 1921 in Kabwe (formerly Broken Hill), Zambia. It is classified as Homo heidelbergensis or sometimes as an archaic Homo sapiens. The skull has a large braincase of about 1,230 cubic centimeters but also retains robust features, such as a prominent brow ridge, broad face, and thick cranial bones. The Kabwe Skull may represent a transitional form between Homo erectus and later anatomically modern humans.

A gene that encodes a lysine demethylase enzyme and plays a crucial role in epigenetic regulation via histone demethylation, influencing gene expression, chromatin structure, and cellular function. Studies have shown a role in tumor suppression.

A unique physical position on a chromosome.

A biological process in which a methyl group (CH₃) is added to a molecule, typically to DNA, proteins, or other cellular structures. In the context of DNA, DNA methylation refers to the addition of a methyl group to the DNA molecule, usually at cytosine bases in a CpG dinucleotide. This modification can regulate gene expression by turning genes on or off without changing the underlying DNA sequence, and it plays a key role in processes like development, aging, and disease. Methylation patterns can be inherited or influenced by environmental factors and lifestyle.

The totality of all organisms (microbes) that live on and in the body.

A period of geological time (781-126,000 years ago). An important time for the diversification of hominins, including the emergence of Neanderthals, Denisovans, and Homo sapiens.

Maternally inherited DNA found only in the mitochondria, the energy producing organelles of eukaryotic cells. Mitochondria are thought to descend from symbiotic bacteria that have become part of eukaryotic cells.

A vast grassland region covering much of Mongolia and extending into parts of northern China and southern Siberia. It is part of the larger Eurasian Steppe and is characterized by its temperate, semi-arid climate and open plains.

The shape or form (outward appearance) of an organism. The branch of biology interested in the form and structure of organisms and their specific structural features.

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.

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.

RNA that is not translated into a protein. Important ncRNAs include transfer RNAs (tRNAs) and ribosomal RNAs (rRNAs), as well as small RNAs such as microRNAs, siRNAs, piRNAs, snoRNAs, snRNAs, exRNAs, scaRNAs and the long ncRNAs such as Xist and HOTAIR.

One of the four classes of major biomolecules. The overall name for DNA and RNA, which are composed of nucleotides. DNA is double-stranded and more stable while RNA is single-stranded and less stable.

The widely accepted theory in human evolution that modern humans originated in Africa and later migrated to other parts of the world, replacing or interbreeding with local archaic human populations, such as Neanderthals and Denisovans.

A person or group whose livelihood is based primarily on the domestication and herding of livestock rather than on farming crops.

The absolute ability of an infectious agent to cause disease or damage in a host.