Archaeology & Evolution Glossary (D)

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


 
dark repair: See excision repair.

Darwinian fitness: The relative reproductive ability of a genotype.

debitage: Detached pieces that are discarded during the reduction process.

debris: See debitage.

decay: In physics, the breaking apart of nuclei into smaller constituent nuclei, releasing energetic particles in the process as there is less total energy.

deciduous (milk) teeth: The first set of teeth in a mammalian jaw, replaced by the permanent dentition.

deduction: A process of reasoning by which more specific consequences are inferred by rigorous argument from more general propositions.

deep-sea cores: Cores drilled from the sea bed that provide the most coherent record of climate changes on a worldwide scale. The cores contain shells of microscopic marine organisms (foraminifera) laid down on the ocean floor through the continuous process of sedimentation. Variations in the ratio of two oxygen isotopes in the calcium carbonate of these shells give a sensitive indicator of sea temperature at the time the organisms were alive.

degeneracy: A multiple coding; more than one codon per amino acid.

degradation control: Regulation of the RNA breakdown rate in the cytoplasm.

deleted: Refers to when a chromosome breaks off spontaneously and is lost.

deletion (deficiency): A chromosomal mutation resulting in the loss of a segment of the genetic material and the genetic information contained therein from a chromosome.

deltoid muscle: A complex shoulder muscle with humerus, calvicle, and scapula attachments that brings the arm up, flexing or extending the humerus depending on which part of the muscle is used.

deme: A local population of a species; the community of potentially interbreeding individuals at a given locality; a population or race sampled over time.

demography: The study of a population’s main life-history parameters – its growth, size, composition, and the age-specific rates of births and deaths.

dendrochronology: The study of tree-ring patterns; annual variations in climatic conditions which produce differential growth can be used both as a measure of environmental change, and as the basis for a chronology.

dendrogram: A branching diagram beginning with a single source.

dental arcade: The tooth row.

dental caries: A pathological process, with destruction of tooth enamel and dentine, leading to infection and loss of the tooth.

dental comb: A primate feature in which the incisors and canines of the lower jaw are of similar size and form, short peg-like teeth that are set horizontally across the front of the mouth.

dental eruption: A continuous process in which teeth emerge out of their crypts (alveolar eruption), through the gums (gingival eruption), and into occlusion with the opposing teeth of the opposite jaw (occlusal eruption), finally ending when the tooth is lost because it erupts out of the mouth.

dental formula: A shorthand notation of the number of incisors, canines, premolars, and molars on one side of the upper and lower dentition of a species (given as a single formula when upper and lower quadrants are the same). For example, the normal adult human dental formula is 2/1/2/3 or 2/1/2/2.

dental hypoplasia: Defects in the enamel of teeth created by interuptions in enamel development, usually because of stresses such as poor nutrition or infection.

dental microwear: Scratches, pits, and gouges on the occlusal surface of teeth that are so small they must be studied by an optical or scanning electron microscope.

dentin: Internal tissue in a tooth crown and tissue of the root, surrounding the pulp cavity and surrounded by the crown enamel. This bone-like substance is sofetr than the enamel.

dentocranial: Pertaining to te teeth and the cranium.

dentofacial: Pertaining to the teeth and face.

dentognathic: Pertaining to the teeth and jaws.

deoxyribonuclease (DNase): An enzyme that catalyzes the degradation of DNA to nucleotides.

deoxyribonucleic acid (DNA): A ploymeric molecule consisting of deoxyribonucleotide building blocks that in a double-stranded, double-helical form is the genetic material of most organisms.

deoxyribonucleotide: The basic building blocks of DNA, consisting of a sugar (deoxyribose), a base, and a phosphate.

deoxyribose: The pentose (five-carbon) sugar found in DNA.

derived feature: An apomorphy, a novel feature.

descent: A relationship defined by connection to an ancestor/ancestress through a culturally recognized sequence of parent-child links.

descent group: A kin group whose membership is based on a rule of descent. Appropriate descent status entitles a person to be a member of the group.

descent rule: A descent principle culturally used to define eligibility for membership in a kin group.

detached piece: A portion of rock removed from an objective piece by percussion or pressure. These are often referred to as flakes, spalls, chips, and debitage.

development: The process of regulated growth that results from the interaction of the genome with cytoplasm and the environment. It involves a programmed sequence of phenotypic events that are typically irreversible.

diachronic: Referring to phenomena as they change over time; i.e. employing a chronological perspective.

diagnosis: In taxonomy, a statement of the characters that uniquely distinguish a taxon from other taxa.

diagnostic: Distinguishing or uniquely characteristic.

diagonal grip: A hand hold in which the object or support (in climbing) is held diagonally across the fingers, without use of the palm.

diagonal parallel flaking: This is similar to parallel flaking except that the flakes are removed at an oblique angle to the objective piece edge.

diakinesis: The stage that follows diplonema and during which the four chromatids of each tetrad are most condensed and the chiasmata often terminalize.

diaphysis: The shaft portion of long bones.

diastema: A space or gap between adjacent teeth in a tooth row, often present to accommodate a projecting canine from the opposing jaw; in the mandible the diastema is between the canine and anterior premolar, in the maxilla between the lateral incisor and canine.

diatom analysis: A method of environmental reconstruction based on plant microfossils. Diatoms are unicellular algae, whose silica cell walls survive after the algae die, and they accumulate in large numbers at the bottom of rivers and lakes. Their assemblages directly reflect the floristic composition of the water’s extinct communities, as well as the water’s salinity, alkalinity, and nutrient status.

dicentric bridge: See dicentric chromosome.

dicentric chromosome: A chromosome with two centromeres. For example, as a result of the crossover between genes B and C in the inversion loop, one recombinant chromatid becomes stretched across the cell as the two centromeres begin to migrate, forming a dicentric bridge.

dideoxy nucleotide: A modified nucleotide that has a 3′-H on the deoxyribose sugar rather than a 3′-OH. If a dideoxy nucleoside triphosphate (ddNTP) is used in a DNA synthesis reaction, the ddNTP can be incorporated into the growing chain. However, no further DNA synthesis can then occur because no phosphodiester bond can be formed with an incoming DNA precursor.

dideoxy (Sanger) sequencing: A method of rapid sequencing of DNA molecules developed by Fred Sanger. This technique incorporates the use of dideoxy nucleotides in a DNA polymerase-catalyzed DNA synthesis reaction.

Dietary Hypothesis: A theory developed by J.T. Robinson to explain the South African australopithecine variations. The hypothesis relates the differences in the gracile and robust South African australopithecines to ecological differences that were reflected in dietary adaptations. The gracile australopithecines are regarded as omnivores and the robust australopithecines as vegetarians.

differential reproduction: Differences in successful reproduction, some individuals have more surviving offspring than others.

differential tooth wear: Differences in the amount of wear between adjacent teeth.

differentiation: An aspect of development that involves the formation of different types of cells, tissues, and organs through the processes of specific regulation of gene expression.

digastric sulcus: A long furrow following the medial surface of the mastoid process, where the digastric muscles attach (muscles important in opening the mandible and moving the hyoid bone).

digit: A finger or toe.

digital flexors: Muscles that cause bending in the fingers or toes.

digitigrade: A type of quadrupedal locomation in which animals support their body weight on their phalanges.

dihybrid cross: A cross between two dihybrids of the same type. Individuals that are heterozygous for two pairs of alleles at two different loci are called dihybrid.

dimorphism: A polymorphic character in which the males and the females of a species differ in some aspect of their anatomy not directly related to reproduction or birth.

dioecious: A term referring to plant species that have both male and female sex organs on different individuals.

diploe: Spongy bone that is sandwiched between inner and outer cortical bone tables.

diploid (2N): A eukaryotic cell with two sets of chromosomes.

diplonema: The second stage of prophase I in which the chromosomes begin to repel one another and tend to move apart.

direct exchange: A system of alliance whereby kin groups exchange wives directly.

discontinuous DNA replication: A DNA replication involving the synthesis of short DNA segments, which are subsequently linked to form a long polynucleotide chain.

discontinuous trait: A heritable trait in which the mutant phenotype is sharply distinct from the alternative, wild-type phenotype.

disjunction: The process in anaphase during which sister chromatid pairs undergo separation.

dispersive model: A DNA replication scheme in which the parental double helix is cleaved into double-stranded DNA segments that act as templates for the synthesis of new double-stranded DNA segments. Somehow, the segments reassemble into complete DNA double helices, with parental and progeny DNA segments interspersed.

distal: Away from the midline of the body, when applied to the appendicular skeleton, or further from the center of the jaw as directed along the tooth row, when applied to teeth.

distal end of flake: The location on a flake that shows the type of termination opposite the striking platform.

diurnal: Usually active during daylight hours.

divergent digits: A finger or toe that is offset in its direction from the remaining digits, allowing some grasping ability.

division of labor: Different cooperative strategies, usually for males and females.

DNA (deoxyribonucleic acid): The molecule that carries the genetic information (genes) in all organisms except the RNA viruses. It consists of two long polysugar-phosphate strands connected by base pairs connecting congruent bases out of a set of four, and twisted in a double helix.

DNA fingerprinting: See DNA typing.

DNA helicase: An enzyme that catalyzes the unwinding of the DNA double helix during replication in E. coli; product of the rep gene.

DNA ligase (polynucleotide ligase): An enzyme that catalyzes the formation of a covalent bond between free single-stranded ends of DNA molecules during DNA replication and DNA repair.

DNA polymerase: An enzyme that catalyzes the synthesis if DNA.

DNA polymerase I: An E. coli enzyme that catalyzes DNA synthesis, originally called the Kornberg enzyme.

DNA primase: The enzyme in DNA replication that catalyzes the synthesis of a short nucleic acid primer.

DNA typing: The use of restriction fragment length polymorphisms DNA analysis to identify an individual.

docking protein: An integral protein membrane of the endoplasmic reticulum (ER) to which the nascent polypeptide-signal recognition particle (SRP)-ribosome complex binds to facilitate the binding of the polypeptide’s signal sequence and associated ribosome to the ER.

dolichocephalic: Longheaded, having a Cephalic Index of less than 75.

domestic group: A social group occupying or centered in a dwelling house, living (and usually eating) together, and characteristically exercising corporate control over family property.

dominance variance (VD): Genetic variance that arises from the dominance effects of genes.

dominant: An allele or phenotype that is expressed in either the homozygous or the heterozygous state.

dominant lethal allele: Allele that will exhibit a lethal phenotype when present in the heterozygous condition.

dorsal: Toward the rearward side of the body; the opposite of ventral. The back of the hand and the “top” of the foot in humans are also considered the dorsal side.

dorsal ridge: A line or ridge formed on the dorsal surface by the previous removal of detached pieces from the objective piece. Also referred to as a dorsal arris.

dorsal surface of flake: The side of a flake or detached piece that shows evidence of previous flake removals or the original surface of the rock.

dorsiflexion: Bending the dorsal surface of the hand (or foot) toward the arm (or leg).

dorsoventral: (Usually motion in) a front to back direction.

dosage compensation: A mechanism in mammals which compensates for X chomosomes in excess of the normal complement. See Barr bodies.

double crossover: Two crossovers occurring in a particular region of a chromosome in meiosis.

double descent: A system whereby two sets of social groups or chategories exist in the same society, one based on patrilineal descent and the other on matrilineal descent.

double fertilization: An event found only in the life cycle of flowering plants. It is the fusing of the sperm cell with the two nuclei of the gametophyte’s central cell to form the cell that will become the endosperm of the seed.

Down syndrome: See trisomy-21.

dowry: Goods sent with a girl at her marriage, either as payment to the husband’s kin or as payment of the women’s share of her family estate.

Dravidian terminology: A mode of kinship reckoning whereby parallel and cross relatives are systematically distinguished; characteristically, but apparently not always, associated with a rule of symetrical alliance.

drift (genetic drift): Changes in gene frequencies due to random or stochastic variation and not the result of selection, mutation, or genic exchanges. Drift changes are most prominent in small populations.

dryopithecine: Member of the subfamily Dryopithecinae.

duplication: A chromosomal mutation that results in the doubling of a segment of a chromosome.



Bibliography

Andrefsky, W., Jr. 1998. Lithics: Macroscopic Approaches to Analysis. Cambridge: Cambridge University Press.
Keesing, R.M. 1975. Kin Groups and Social Structure. Fort Worth: Harcourt Brace.
Renfrew, C., and P. Bahn. 1996. Archaeology: Theories, Methods, and Practice. New York: Thames and Hudson Inc.
Russell, P.J. 1998. Genetics. Menlo Park: Addison Wesley Longman, Inc.
Wolpoff, M. 1999. Paleoanthropology. second edition. Boston: McGraw-Hill.