Chapter 13-15 2
Terms
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- oncogene
- 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.
- Spindle assembly checkpoint
- A mechanism that arrests the cell division cycle until the spindle is properly deployed.
- Centrosome Duplication checkpoint
- A mechanism that arrests the cell cycle while the centrosome (the spindle-organizing center) remains undivided.
- checkpoint
- Any mechanism that arrests the cell cycle until one or more essential processes are completed
- Proto-oncogene
- A eukaryotic gene that functions to promote cellular proliferation or inhibit apoptosis, in which gain-of-function mutations (oncogenes) are associated with cancer progression.
- tumor-suppressor gene
- A gene that normally controls cell proliferation or that activates the apoptotic pathway, in which loss-of-function mutations are associated with cancer progression.
- BAX protein
- A tumor-suppressor protein that promotes apoptosis. Loss of function leads to deletions or additions of nucleotides.
- Loss of herterozygosity
- 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.
- Promoter fusion
- Joining of the promoter region of one gene with the protein-coding region of another.
- Gene fusion
- A new gene created by the joining of DNA from two preexisting genes
- Chimeric gene
- A gene produced by recombination, chromosome rearrangement, or genetic engineering that is a mosaic of DNA sequences from two or more differente genes.
- molecular evolution
- A study of how and why the sequences of macromolecules change through time.
- molecular symatics
- 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.
- Taxon/taxa
- 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.
- Distance Matrix
- A matrix showing the amount of sequence divergence between all possible pairs of a set of protein or nucleic acid sequences.
- Neighbor Joining
- 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.
- Bootstrapping
- 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.
- Molecular clock
- 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.
- Selectivly Neutral Mutation
- A mutation that has no (or negligible) effects on fitness.
- pseudogene
- 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.
- Orthologous genes
- Genes that share a common ancestral gene through the process of speciation.
- Paralogous genes
- Genes that share a common ancestral gene through the process of gene duplication within a species.
- Subfunctionalization
- Evolutionary change in a gene that results in loss of one or more of its functional or regulatory motifs.
- Geneotype frequency
- The proportion of memebers of a pop that are of a prescribed genotype
- Allele frequency
- The relative proportion of all alleles of a gene that are of designated type.
- Hardy-Weinberg principle
- The genotype frequencies expected with random mating.
- Inbreeding
- Mating between relatives
- Polymorphic gene
- A gene for which there is more than one relative common allele in a pop
- Inbreeding coefficient (F)
- 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.
- Evoltion
- Cumulative change in the gentic characteristics of a species through time
- Migration
- Movement of organisms among subpopulations
- Natural Selection
- 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.
- Random genetic drift
- Fluctuation in allele frequency from generation to generation resulting from restricted pop size
- Maternal Inheritance
- Extranuclear inheritance of a trait through cytoplasmic factors or organelles contributed by the female gamete.
- Mitochondrial DNA
- Is maternally inherited and shows maternal inheritance (pg. 521-523)
- Most recent common ancestor
- In a phylogenetic tree, the most recent node that unites a particular subset of sequences, characters, or species.
- Multifuctional/complex traits
- A multifactorial trait influenced by multiple genetic and environmental factors, each of relatively small effect, and their interactions.
- Genetic architecture
- Of complex trait, specification of the genetic and environmental factors that contribute to the trait, and their interactions.
- Quantitative trait
- 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
- Continuous trait
- Trait in which the possible phenotypes have a continuous range from one extreme to other rather than falling into discrete classes.
- Categorical trait
- A complex trait in which each possible phenotype can be classified into one of a number of discrete categories. aka meristic trait
- Threshold trait
- 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.
- Normal distribution
- 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.
- Genotypic variance
- The part of the phenotypic cariance that is attributable to differences in genotype
- Environmental variance
- The part of the phenotypic variance that is attributable to diff. in environment
- Total (phenotypic) variance
- Summation of all sources of genetic and environmental variation
- Genotype-by-environment Association
- condition in which genetic and environmental effects on a trait are not in random combinations.
- Genotype-by-environment interaction
- Condition in which genetic and environmental effects on a trait are not additive.
- Broad-sense heritability
- The ratio of genotypic variance to total phenotypic variance.
- Artificial selection
- Selection imposed by a breeder in which organisms of only certain phenotypes are allowed to breed.
- Truncation point
- In artifical selection, the value of the phenotype that determines which organisms will be retained for breeding and which will be culled.
- Narrow-sence heritabliity
- 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.
- Additive effects
- 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
- Selection limit
- The condition in which a pop no longer responds to artificial selection for a trait
- Correlated response
- Change in the mean in one trait in a pop accompanying selection for another trait
- Inbreeding depression
- A phenomenon in which the average value of a quantitative trait in a pop undergoes progressive deterioration as the level of inbreeding increases
- Heterosis
- The superiority of hybrids over either inbred partent with respect to one or more traits; aka hybrid vigor
- Liability
- Risk, particularly toward a threshold type of quantitative trait.
- Quantitative trail locus (QTL)
- A locus segregating for alleles that have diff. measureable effects on the expression of a quantitative trait
- Candidate gene
- 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.