Chapter 13-15

Front 1

oncogene

Back 1

A gain-of-function mutation in a cellular gene, called a proto-oncogene, whose normal function is to promote cellular proliferation or inhibit apoptosis;oncogenes are often associated with tumor progression.

Front 2

Spindle assembly checkpoint

Back 2

A mechanism that arrests the cell division cycle until the spindle is properly deployed.

Front 3

Centrosome Duplication checkpoint

Back 3

A mechanism that arrests the cell cycle while the centrosome (the spindle-organizing center) remains undivided.

Front 4

checkpoint

Back 4

Any mechanism that arrests the cell cycle until one or more essential processes are completed

Front 5

Proto-oncogene

Back 5

A eukaryotic gene that functions to promote cellular proliferation or inhibit apoptosis, in which gain-of-function mutations (oncogenes) are associated with cancer progression.

Front 6

tumor-suppressor gene

Back 6

A gene that normally controls cell proliferation or that activates the apoptotic pathway, in which loss-of-function mutations are associated with cancer progression.

Front 7

BAX protein

Back 7

A tumor-suppressor protein that promotes apoptosis. Loss of function leads to deletions or additions of nucleotides.

Front 8

Loss of herterozygosity

Back 8

Loss of the presence of the wildtype allele, or loss of its function, in a heterozygous cell, enabling the phenotype of a recessive mutant allele to be experssed; mechanisms for loss of heterozygosity include chromosome loss, gene conversion, and mutation.

Front 9

Promoter fusion

Back 9

Joining of the promoter region of one gene with the protein-coding region of another.

Front 10

Gene fusion

Back 10

A new gene created by the joining of DNA from two preexisting genes

Front 11

Chimeric gene

Back 11

A gene produced by recombination, chromosome rearrangement, or genetic engineering that is a mosaic of DNA sequences from two or more differente genes.

Front 12

molecular evolution

Back 12

A study of how and why the sequences of macromolecules change through time.

Front 13

molecular symatics

Back 13

A group of statistical methods for estimating gene trees and often, by inference, the evolutionary relationships among the taxa of which the genes are representative.

Front 14

Taxon/taxa

Back 14

A population, species, or other group of organisms of which a protein or nucleic acid sequence, or a set of such sequences, is regarded as representative.

Front 15

Distance Matrix

Back 15

A matrix showing the amount of sequence divergence between all possible pairs of a set of protein or nucleic acid sequences.

Front 16

Neighbor Joining

Back 16

A method for estimating a gene tree in which pairs of taxa are joined sequentially according to which pair are separated by the shortest distance.

Front 17

Bootstrapping

Back 17

Analysis of multiple data sets formed by ramdom sampling with replacement from an actual data set in order to estimate a degree or confidence in a particular branch or branching pattern in a gene tree.

Front 18

Molecular clock

Back 18

A condition in which a protein or nucleic acid molecule has the same probability of change per unit time in every branch of a gene tree.

Front 19

Selectivly Neutral Mutation

Back 19

A mutation that has no (or negligible) effects on fitness.

Front 20

pseudogene

Back 20

A DNA sequence that is not functional because of one or more mutations but that has a functional conterpart in the same organism; pseudogenes are regarded as mutated forms of ancient gene duplications.

Front 21

Orthologous genes

Back 21

Genes that share a common ancestral gene through the process of speciation.

Front 22

Paralogous genes

Back 22

Genes that share a common ancestral gene through the process of gene duplication within a species.

Front 23

Subfunctionalization

Back 23

Evolutionary change in a gene that results in loss of one or more of its functional or regulatory motifs.

Front 24

Geneotype frequency

Back 24

The proportion of memebers of a pop that are of a prescribed genotype

Front 25

Allele frequency

Back 25

The relative proportion of all alleles of a gene that are of designated type.

Front 26

Hardy-Weinberg principle

Back 26

The genotype frequencies expected with random mating.

Front 27

Inbreeding

Back 27

Mating between relatives

Front 28

Polymorphic gene

Back 28

A gene for which there is more than one relative common allele in a pop

Front 29

Inbreeding coefficient (F)

Back 29

A measure of the genetic effects of inbreeding in terms of the proportionate reduction in heterozygosity in an inbred organism compared with the heterozygosity expected with ramdom mating.

Front 30

Evoltion

Back 30

Cumulative change in the gentic characteristics of a species through time

Front 31

Migration

Back 31

Movement of organisms among subpopulations

Front 32

Natural Selection

Back 32

The process of evolutionary adaptation in which the genotypes genetically best suited to survive and reproduce in a particular environment give rise to a disproportionate share of the offspring oand so gradually increase the overall ability of the pop to survive and reproduce in that environment.

Front 33

Random genetic drift

Back 33

Fluctuation in allele frequency from generation to generation resulting from restricted pop size

Front 34

Maternal Inheritance

Back 34

Extranuclear inheritance of a trait through cytoplasmic factors or organelles contributed by the female gamete.

Front 35

Mitochondrial DNA

Back 35

Is maternally inherited and shows maternal inheritance (pg. 521-523)

Front 36

Most recent common ancestor

Back 36

In a phylogenetic tree, the most recent node that unites a particular subset of sequences, characters, or species.

Front 37

Multifuctional/complex traits

Back 37

A multifactorial trait influenced by multiple genetic and environmental factors, each of relatively small effect, and their interactions.

Front 38

Genetic architecture

Back 38

Of complex trait, specification of the genetic and environmental factors that contribute to the trait, and their interactions.

Front 39

Quantitative trait

Back 39

A trait, typically measured on a continuous scale, such as height or weight- that results from the combined action of several or many genes in conjunction with environmental factors

Front 40

Continuous trait

Back 40

Trait in which the possible phenotypes have a continuous range from one extreme to other rather than falling into discrete classes.

Front 41

Categorical trait

Back 41

A complex trait in which each possible phenotype can be classified into one of a number of discrete categories. aka meristic trait

Front 42

Threshold trait

Back 42

A trait with a continuous distributed liability or risk;organisms with a liability greater than a critical value (the threshold) exhibit the phenotype of interest, such as a disorder.

Front 43

Normal distribution

Back 43

A symmetrical bell-shaped distribution characterized by the mean and the variance; in a normal distribution, approximately 68% observations within 1 standard dev. 95% within 2.

Front 44

Genotypic variance

Back 44

The part of the phenotypic cariance that is attributable to differences in genotype

Front 45

Environmental variance

Back 45

The part of the phenotypic variance that is attributable to diff. in environment

Front 46

Total (phenotypic) variance

Back 46

Summation of all sources of genetic and environmental variation

Front 47

Genotype-by-environment Association

Back 47

condition in which genetic and environmental effects on a trait are not in random combinations.

Front 48

Genotype-by-environment interaction

Back 48

Condition in which genetic and environmental effects on a trait are not additive.

Front 49

Broad-sense heritability

Back 49

The ratio of genotypic variance to total phenotypic variance.

Front 50

Artificial selection

Back 50

Selection imposed by a breeder in which organisms of only certain phenotypes are allowed to breed.

Front 51

Truncation point

Back 51

In artifical selection, the value of the phenotype that determines which organisms will be retained for breeding and which will be culled.

Front 52

Narrow-sence heritabliity

Back 52

The fraction of the phenotypic variance revealed as resemblance between parents and offspring; technically the ratio of the additive genetic variance to the total phenotypic variance.

Front 53

Additive effects

Back 53

Each heterozygous shows a phenotype that is exactally intermediate between the phenotypes of the respective homozygous genotypes and that the effects are also additive across loci

Front 54

Selection limit

Back 54

The condition in which a pop no longer responds to artificial selection for a trait

Front 55

Correlated response

Back 55

Change in the mean in one trait in a pop accompanying selection for another trait

Front 56

Inbreeding depression

Back 56

A phenomenon in which the average value of a quantitative trait in a pop undergoes progressive deterioration as the level of inbreeding increases

Front 57

Heterosis

Back 57

The superiority of hybrids over either inbred partent with respect to one or more traits; aka hybrid vigor

Front 58

Liability

Back 58

Risk, particularly toward a threshold type of quantitative trait.

Front 59

Quantitative trail locus (QTL)

Back 59

A locus segregating for alleles that have diff. measureable effects on the expression of a quantitative trait

Front 60

Candidate gene

Back 60

A gene proposed to be involved in the genetic determination of a trait because of the role of the gene product in the cell or organism.