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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.
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