Archaeology & Evolution Glossary (G)

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


 
gallery forest: A stretch of forest along a river or stream.

gamete: Mature reproductive cells that are specialized for sexual fusion. Each gamete is haploid and fuses with a cell of similar origin but of opposite sex to producea diploid zygote.

gametogenesis: The formation of male and female gametes by meiosis.

gametophyte: The haploid sexual generation in the life cycle of plants that produces the gametes.

gathering: Food acquisition with postponed consumption.

GC box: A eukaryotic promoter element with the consensus sequence 5′-GGGCGGG-3′ that can be found in either orientation upstream of the transcription initiation site. The GC boxes appear to help the RNA polymerase near the transcription start point.

gene (Medelian factor): A unit of inheritence carried on a chromosome, transmitted from generation to generation by the gametes and controlling some aspects of the development of an individual.

genealogical species: Species that are defined by common ancestry and are treated as distinct individuals with definite beginnings and ends.

gene flow: A form of genic exchange in which genetic material is transferred between populations because of interbreeding or mate exchange between them.

gene frequency: The percentage or proportion of a given allele in a sample.

gene locus: See locus.

gene marker: See genetic marker.

gene mutation: A heritable alteration of the genetic material, usually from one allelic form to another.

gene pool: The total genetic information encoded in the total genes in a breeding population existing at a given time.

generalized: (1) Primitive or plesiomorphic, similar to the ancestral condition; (2) adapted to a broad range of resources.

generalized transduction: A type of transduction in which any gene may be transferred between bacteria.

gene redundancy: A situation in which tRNA genes occur two or more times in the E. coli chromosome.

gene regulatory elements: Base-pair sequences associated with a gene, which are involved in the regulation of gene expression.

gene segregation: See principle of segregation (first law).

genetic code: The base-pair information that specifies the amino acid sequence of a polypeptide.

genetic correlation (pleiotropy): Covariation of features in populations because they share some genes. An association between the genes that determine two traits.

genetic counseling: The procedures whereby the risks of prospective parents having a child who expresses a genetic disease are evaluated and explained to them. The genetic counselor typically makes predictions about the probabilities of particular traits (deleterious or not) occurring among children of a couple.

genetic drift: A mechanism for evolutionary change caused by the random fluctuations of gene frequencies from one generation to the next, or from any form of random sampling from a gene pool. Any change in gene frequency due to chance in a population.

genetic engineering: The alteration of the genetic constitution of cells or individuals by directed and selective modification, insertion, or deletion of an individual gene or genes. In some cases, novel gene combinations are made by joining DNA fragments from different organisms.

genetic map (linkage map): A representation of the genetic distance separating nonallelic gene loci in a linkage structure.

genetic mapping: The uses of genetic crosses to locate genes in chromosomes relative to one another.

genetic marker (gene marker): Any genetically controlled phenotypic difference used in genetic analysis, particularly in the detection of genetic recombination events.

genetic recombination: A process by which parents with different genetic characters give rise to progeny so that genes in which the parents differed are associated in new combinations. For example, from A B to a b the recombinants A b and a B are produced.

genetic reorganization: The dislinking of co-adapted alleles (alleles with interdependent frequencies) due to random fluctuations because of small population effects during peripatric speciation, followed by the establishment of new co-adapted allele systems.

genetics: The science of heredity that involves the structure and function of genes and the way genes are passed from one generation to the next.

genetic variance (VG): Genetic sources of phenotypic variation among individuals of a population; includes dominance genetic variance, additive genetic variance, and epistatic genetic variance.

genic exchange: The sharing of genetic material because of gene flow or migration.

genioglossal pit: The notch on the inside border of the mandibular symphysis marking the origin of the genioglossus (tongue) muscle.

genome: The entire DNA component of a cell, a structured array consisting of genes and their parts, units of DNA replication, and nonfunctioning regions.

genomic imprinting: Phenomenon in which the expression of certain genes is determined by whether the gene is inherited from the female or male parent.

genomic library: The collection of molecular clones that contain at least one copy of every DNA sequence in the genome.

genotype: The genetic make-up of an organism, its total genetic material.

genotypic frequencies: The frequencies or percentages of different genotypes found within a population.

genotypic sex determination: The process by which the sex chromosomes play a decisive role in the inheritance and determination of sex.

genus (genera): A group of closely related species, a monophyletic category for the taxon above the species level that includes one or more species.

geochemical analysis: The investigatory technique which involves taking soil samples at regular intervals from the surface of a site, and measuring their phosphate content and other chemical properties.

geomagnetic reversal: An aspect of archaeomagnetism relevant to the dating of the Lower Paleolithic, involving complete reversals in the earth’s magnetic field.

geomorphology: A subdiscipline of geography, concerned with the study of the form and development of the landscape, it includes such specializations as sedimentology.

germ-line mutations: Mutations in the germ-line of sexually reproducing organisms may be transmitted by the gametes to the next generation, giving rise to an individual with the mutant state in both its somatic and germ-line cells.

gestation: The period from fertilization to birth.

glabella: A place on the midline of the frontal bone between the browridges, superciliary arches, or upper orbital borders.

glaciation: Ice age, the temporary enlargement of continental ad momentum glaciers associated with worldwide climate changes.

glenoid fossa: (1) The mandibular fossa; (2) or the glenoid fossa of the gleno-humeral joint.

glenoid joint: (1) The temporo-mandibular articulation; (2) the socket part of the shoulder ball-and-socket joint on the scapula.

glottochronology: A controversial method of assessing the temporal divergence of two languages based on changes of vocabulary (lexicostatistics), and expressed as an arithmetic formula.

glucose effect: See catabolite repression.

gluteus maximus: Large muscle extending from the lateral and rear surface of the ilium to the gluteal tuberosity of the femur, causing extension and rotation at the top.

gluteus medius: Muscle extending from the lateral surface of the ilium to the greater trochanter of the femur, causing abduction at the hip.

gluteus minimus: Large muscle extending from the lateral surface of the ilium to the greater trochanter of the femur, causing abduction and rotation at the hip.

Goldberg-Hogness box (TATA box, TATA element): Found approximately at position-30 from the transcription initiation site. The Goldberg-Hogness sequence is considered to be the likely eukaryotic promotor sequence. The consensus sequence for the Goldberg-Hogness box is TATAAAAA.

gonial angle: The smoothly curced area where the back of the ramus meets the bottom of the corpus.

gracile: Slender, delicately built, weak muscle attachments or bony butresses. A relative condition referenced to another condition.

grade: A grouping characterized by a general level of organization (or sharing a suite of features). Grades composed of independent lineages that may or may not be monophyletic.

gradualism: A theory that evolution progresses by the extension of microevolutionary processes over long periods of time, the gradual modification of populations. The concept does not imply continuous evolution, or evolution at a constant rate.

graminivore: An animal that eats primarily grains; often used to describe seed-eating.

great apes: The four large living apes: bonobos, chimpanzees, gorillas, and orangutans. Great apes are not a monophyletic group.

greater sciatic notch: U-shaped notch at the back of the innominate characteristics of bipedal hominid pelves caused by the rearward and inferior displacement of the sacrum relative to the ape anatomy.

greater trochanter: Very large process on the lateral and proximal end of the femur shaft, for the attachment of muscles that stabilize the hip during one-legged balance (whether in standing or in bipedal locomotion).

gregarious: Social orientation to behavior, living in regular social groups.

grind: In chewing, the action resulting from applied forces with components that are both perpendicular and parallel to the plane of contact between the teeth.

grooming: Cleaning the body surface by licking, biting, picking with fingers or claws, or other kinds of manipulation.

group I-intron self-splicing: See self-splicing.

group selection: Evolutionary process involving differential survival and reproduction of competing groups.

guanine (G): Purine base found in RNA and DNA. In double-stranded DNA, guanine pairs with the pyrimidine cytosine.

gummivore: An animal specializing in gums, saps, and other tree exudates.

gyrus: The “hill” of the convolutions on the surface of the brain caused by the folding of the cortex.

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.