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race: A group of individuals
geographically (and for humans also culturally) determined who share
a common gene pool and varying combinations of distinguishing characteristics.
racemization: The conversion
of some amino acids from their original "left-handed"
form to "right-handed" form, after death, so that the
two forms occur iin about equal numbers.
radial notch: Smooth
facet on the ulna's proximal shaft where the head of the radius
articulates during radial rotation.
radioactive decay:
The regular process by which radioactive isotopes braek down into
their decay products with a half-life which is specific to the isotope
in question.
radiocarbon dating:
An absolute dating method that measures the decay of the radioactive
isotope of carbom (14C) in organic material.
radioimmunoassay: A
method of protein analysis whereby it is possible to identify protein
molecules surviving in fossils which are thousands and even millions
of years old.
radiometric: A process
based on nuclear decay, as in radiometric dating.
radius: One of two
long bones of the forearm, on the thumb side, which rotates against
the ulna so that its lower end, the hand, can be turned.
raised beaches: These
are remnants of former coastlines, usually the result of processes
such as isostatic uplift or tectonic movements.
ramage: A term used
by Firth to denote a cognatic descent group, and by Sahlins to denote
a descent system where local descent groups are ranked according
to senoirity of descent.
ramus: The portion
of bone at an angle to the body, as in ascending ramus (mandible),
or pubic ramus (innominate).
random mating: Matings
between genotypes occurring in proportion to the frequencies of
the genotypes in the population.
range: Territory normally
occupied.
ranked societies: Societies
in which there is unequal access to prestige and status.
rDNA repeat units:
The tandem arrays of rRNA genes, 18S-5.8S-28S, repeated many times
along the chromosome.
recapitulation: The
theory that "ontogeny recapitulates phylogeny."
recessive: An allele
or phenotype that is expressed only in the homozygous state.
recessive lethal allele:
An allele that causes lethality when it is homozygous.
reciprocal altruism:
Exchange of favors by two individuals in which one individual temporarily
sacrifices potential fitness in expectation of a return.
reciprocal cross: A
cross of males and females of one trait with males and females of
another trait. In the garden pea example, a reciprocal cross for
smooth and wrinkled seeds is smooth female X wrinkled male and wrinkled
female X smooth male.
recombinant chromosome:
A chromosome that emerges from meiosis with a combination of genes
different from a parental combination of genes.
recombinant DNA molecule:
A new type of DNA sequence that has been constructed or engineered
in the test tube from two or more distinct DNA sequences.
recombinant DNA technology:
A collection of experimental procedures that allow molecular biologists
to splice a DNA fragment from one organism into DNA from another
organism and to clone the new recombinant DNA molecule. It includes
the development and application of particular molecular techniques,
such as biotechnology or genetic engineering. This technology is
important, for example, in the production of antibiotics, hormones,
and other medical agents used in the diagnosis and treatment of
certain genetic diseases.
recombinants: The individuals
or cells that have nonparental combinations of genes as a result
of the processes of genetic recombination.
recombination: The
bringing together of novel combinations of genes by the process
of meiosis and crossover during sexual reproduction. See genetic
recombination.
redistribution: A mode
of exchange that implies the operation of some central organizing
authority. Goods are recieved or appropriated by the central authority,
and subsequently some of them are sent by that authority to other
loactions.
refitting: Sometimes
referred to as conjoining, this entails attempting to put stone
tools and flakes back together again, and provides important information
on the processes involved in the knapper's craft.
refutationist view:
Approach which holds that science consists of theories about the
empirical world, that its goal is to develop better theories, which
is achieved by finding mistakes in existing theories, so that it
is crucial that theories be falsifiable (vulnerable to error and
open to testing). The approach, developed by Karl Popper, emphasizes
the importance of testability as a component of scientific theories.
regional continuity:
The observation that there is a sequence of anatomical features,
often found together, spanning the time from earlier to later populations
in a geographic region, that seems to reflect some degree of ancestral-descendent
relationship.
regression: A statistical
analysis assessing the association between two variables.
regression line: A
mathematically computed line that represents the best fit of a line
to the points.
regulated gene: A gene
whose activity is controlled in response to the needs of a cell
or organism.
regulatory factors:
Proteins active in the activation or repression of transcription
of the gene.
relationship systems:
term used by Needham and other proponents of the "category"
approach to kinship terms to denote "kinship" terminologies.
relative dating: Determination
of the ordered sequence of sites, artifacts, or fossils.
release factors: See
termination factors.
religion: A framework
of beliefs relating to supernatural or superhuman beings or forces
that transcend the everyday material world.
replica plating: The
procedure for transferring the pattern of colonies from a master
plate to a new plate. In this procedure, a velveteen pad on a cylinder
is pressed lightly onto the surface of the master plate, thereby
picking up a few cells from each colony to inoculate onto the new
plate.
replication bubble:
Opposing replication forks found with the local denaturing of DNA
during replication.
replication fork: A
Y-shaped structure formed when a double-stranded DNA molecule unwinds
to expose the two single-stranded template strands for DNA replication.
replication machine
(replisome): The complex formed by the close association of the
key proteins used during DNA replication.
replicon (replication
unit): The stretch of DNA in eukaryotes from the origin or replication
to the two termini of replication on each side of the origin.
repressor: See repressor
gene.
repressor gene: A regulatory
gene whose product is a protein that controls the transcriptional
activity of a particular operon.
repressor molecule:
The protein product of a repressor gene.
repulsion: An arrangement
in which each homologous chromsome carries the wild-type allele
of one gene and the mutant allele of the other one.
residence rules: Conventions
for residence by a couple after marriage, defining whether they
reside with husband's kin, wife's kin, or others.
resorb: To destroy
and remove bone or parts of bone by osteoclasts (bone cells with
digestive enzymes).
restriction endonucleases
(restriction enzymes): Enzymes important for analyzing DNA and for
constructing recombinant DNA molecules because of their ability
to cleave double-stranded DNA molecules at specific nucleotide pair
sequences.
restriction enzymes:
See restriction endonucleases.
restriction fragment
length polymorphism (RLFPs): The different restriction maps that
result from different patterns of distribution of restriction sites.
They are detected by the presence of restriction fragments of different
lengths on gels.
restriction map: A
genetic map of DNA showing the relative positions of restriction
enzyme cleavage sites.
restriction site linker:
A relatively short, double-stranded oligodeoxyribonucleotide about
8 to 12 nucleotide pairs long that is synthesized by chemical means
and that contains the cleavage site for a specific restriction enzyme
within its sequence.
retouch: Intentional
modification of a stone tool edge by either pressure or percussion
flaking technique. Modification by use is considered usewear as
opposed to retouch.
retract: Pull backwards.
retromolar space: A
space or gap at the rear of a mandible between the back of the last
molar and the anterior edge of the ascending ramus where it crosses
the alveolar margin.
retrovirus: Single-stranded
DNA virus that replicates via double-stranded DNA intermediates.
The DNA integrates into the host's chromosome where it can be transcribed.
reversed polarity epoch:
Period of geological time in which the earth's magnetic field is
directly the opposite to what it is at present (the north end of
a compass would point north, rather than south).
reverse genetics: See
positional cloning.
reverse mutation (reversion):
A mutational change from a mutant allele back to a wild-type allele.
reverse transcriptase:
An enzyme (an RNA-dependent DNA polymerase) that makes a complementary
DNA copy of an mRNA strand.
rhinarium: A hairless
patch of skin between the nose and upper lip that is kept moist
to enhance the sense of smell.
rhizotic: Rooted, a
model of change in which elements (populations cultures, languages)
are derived from or rooted in several different antecedents.
rhyolite: The fine-grained
member of the granite family of igneouos rocks. It is light in color
and usually contains pink feldspar.
ribonuclease (RNase):
An enzyme that catalyzes the degradation of RNA to nucleotides.
ribonucleic acid (RNA):
A usually single-stranded polymeric molecule consisting of ribonucleotide
building blocks. RNA is chemically very similar to DNA. The three
major types of RNA in cells are ribosomal RNA (rRNA), transfer RNA
(tRNA), and messenger RNA (mRNA), each of which performs an essential
role in protein synthesis (translation). In some viruses, RNA is
the genetic material.
ribonucleotide: The
basic building block of RNA consisting of a sugar (ribose), a base,
and a phosphate.
ribose: The pentose
sugar component of the nucleotide building block of RNA.
ribosomal DNA (rDNA):
The regions of the DNA that contain the genes for the rRNAs in prokaryotes
and eukaryotes.
ribosomal proteins:
The proteins that along with rRNA molecules comprise the ribosomes
of prokaryotes and eukaryotes.
ribosomal RNA (rRNA):
The RNA molecules of discrete sizes that along with ribosomal proteins
comprise ribosomes of prokaryotes and eukaryotes.
ribosome: A complex
cellular particle composed of ribosomal protein and rRNA molecules
that is the site of amino acid polymerization during protein synthesis.
ribosome-binding site:
The nucleotide sequence on an mRNA molecule on which the ribosome
becomes oriented in the correct reading frame for the initiation
of protein synthesis.
ridge: A narrow roughened
elevation on a bone's surface.
R looping (R loops):
A technique developed by M. Thomas, R. White, and R. Davis in which
molecules of double-stranded DNA are incubated at temperatures below
their denaturing temperature to open up short stretches of the DNA
double helix so that single-stranded RNA molecules can begin to
form DNA/RNA hybrids where the two are complementary. The DNA/RNA
hybrid forms an R loop by displacing a single-stranded section of
DNA.
RNA: See ribonucleic
acid.
RNA editing: Posttranscriptional
insertion and/or deletion of nucleotides in an mRNA molecule.
RNA ligase: An enzyme
that splices together the RNA pieces once the intervening sequence
is removed from the pre-tRNA.
RNA polymerase: An
enzyme that catalyzes the synthesis of RNA molecules from a DNA
template in a process called trascription.
RNA polymerase I: An
enzyme in eukaryotes located in the nucleolus that catalyzes the
transcription of the 18S, 5.8S, and 28S rRNA genes.
RNA polymerase II:
An enzyme in eukaryotes found only in the nucleoplasm of the nucleus.
It catalyzes the transcription of mRNA-coding genes.
RNA polymerase III:
An enzyme in eukaryotes found only in the nucleoplasm. It catalyzes
the transcription of the rRNA and 5S rRNA genes.
RNA primer: A preexisting
polynucleotide chain in DNA replication to which new nucleotides
can be added.
RNA processing control:
The second level of control of gene expression in eukaryotes. This
level involves regulating the production of mature RNA molecules
from precursor-RNA molecules.
RNA synthesis: See
transcription.
Robertsonian translocation:
A type of nonreciprocal translocation in which the long arms of
two nonhomologous acrocentric chromosomes become attached to a single
centromere.
robust: A large or
heavily built body or body part.
Robusticity Index:
An index obtained by expressing a diameter (or circumference) of
a bone in terms of its length.
rock: Any naturally
formed, firm and coherent aggregate or mass of mineral matter that
constitutes part of the Earth's crest.
rock composition: Refers
to the chemical elements and mineral from which rocks are created.
rock texture: Refers
to the size, shape, and relationship of individual particles in
a rock.
rock varnishes: Natural
accretions of magnesium and iron oxides, togetehr with clay minerals
and organic matter, which can provide valuable environmental evidence.
Their study, when combined with radiocarbon methods, can provide
a minimum age for some landforms, and even some types of stone tools
which can accumulate varnish.
roll-out: See hinge
termination.
Romer's Rule: The generalization
that new adaptations are often allowed by evolutionary changes that
initially better adapt a species to its old way of life.
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