GENETIC TERMS （IN ALPHABATIC ORDER）
Abundance: of an mRNA is the average number of molecules per cell.
Abundant mRNA: consisting of a small number of individual species, each present in a large
number of copies per cell.
Acentric fragment (of a chromosome): lacks a centromere and is lost at cell division.无中心粒的片断
Acentric chromosome 近端着丝的染色体
Acquired genetic mutation
Active site： 活性中心
Additive genetic effects
Additive genetic variance
Affected relative pair
Alien addition lines
Alien cytoplasm substitution
Allele exclusion: 等位基因排斥
Allele specific associated primer
Allele specific oligo
Allele specific polymerase chain reaction
Allosteric control: 变构/异构控制
Amber suppressor: 琥铂抑制子
Aminoacyl site (A site)
Aminoacyl tRNA synthetase
Amplified fragment lenght polymorphism
Anticoding strand： 反密码链
Antiparallel strand: 反向平行链
Antisense RNA-ribozyme chimeric DNA
Antisense strand 反义链
Antitermination protein: 抗终止蛋白
AP endonuclease AP核酸内切酶
Apurinic endonuclease (AP endonuclease)
Arbitrary primed polymerase chain reaction
Archebacteria (archae-bacteria) 古细菌，原始细菌
Attenuation 衰减, 减毒
Autonomous controlling element
Autosomal recessive disorder
Back mutation 回复突变
Bacterial attachment site
Balbiani ring: an extremely large puff(疏松部) at a band(分带) of a polytene chromosome
Base pair (bp)
Base sequence analysis
Base substitution mutation
Becquerel (Antoine Henri Becquerel, French physicist)
bidirectional replication 双向复制
blunt ends 平齐末端
Bovine spongiform encephalopathy (BSE)
branch migration 分枝移动
BRCAI and BRCAZ breeding
Bulked segregant analysis
Cap: the structure at the 5‘ end of eukaryotic mRNA, introduced after transcription by linking the
terminal phosphate of 5‘ GTP to the terminal base of the mRNA.
CAP protein: a positive regulator protein activated by cyclic AMP. It si needed for RNA
polymerase to initiate transcription of certain operons of E. Coli.
Capsid: external protein coat of a virus particle. （病毒的）衣壳，壳体
Catabolite activator protein
Catabolite repressio 分解产物（降解物）阻遏
C-banding: a technique for generating stained regions around centromeres
CAAT box: part of a conserved sequence located upstream of the startpoints of eukaryotic
transcription units; it is recognized by a large group of transcription factors.
cDNA: a single-stranded DNA complementary to an RNA, synthesized from it by reverse
transcription in vitro.
Cell cycle: the period from one division to the next
Cell lysate on cellophane disk
Cellular oncogene (C-onc)
C genes: code for the constant regions of immunoglobulin protein chain.
C value: the total amount of DNA in a haploid genome
Chiasma （染色体）交叉(pl. Chiasmata)
Chromosome balance translocation
Chromosome theory of heredity
ClB method (*)
Cleaved amplified pollymorphic sequence
Cloning vector 克隆载体
Closed reading frame
Cognate tRNA: those recognized by a particular aminoacyl-tRNA synthetase
Cohesive end (cos)
Colony hybridization assay
Complementary DNA (cDNA)
Compound heterozygote 杂合体，异型合子（就某一性状具有不同的等位基因的个体）
Concatenated circle (of DNA): interlocked like rings on a chain
Consensus sequence 同感序列
Constant region (C region)
Constitutive stable replication (c SDR)
Contigs: a set of cloned DNA fragments overlapping in such a way as to provide unbroken
coverage of a contiguous(紧接的,临近的) region of the genome; a contig contains no gaps.
Contiguous gene syndrome
Controlling element (of maize)
Coordinate regulation: refers to the common control of a group of genes
Copy number mutant (cop)
Cordycepin: 3‘ deoxyadenosine, an inhibitor of polyadenylation of RNA 3‘脱氧腺苷
Cotransfection: simultaneous transfection of two markers
Covalently closed circle
Creutzfeldt-Jakob Desease (CJD)
Crossing over 交换（细胞第一次减数分裂的粗线期中，配对同源染色体的非姊妹染色单体之间的遗传物质进行交换，导致新的基因组合）
Crossover fixation: a possible consequence of unequal crossing-over that allows a mutation in one
member of a tandem cluster to spread through the whole cluster (or to be eliminated)
Cruciform: the structure produced at inverted repeats of DNA if the repeated sequence pairs with
its complement on the same strand.
Cryptic satellite: a satellite DNA sequence not identified as such by a separate peak on a density
gradient; that is, it remains present in main-band DNA.
Cryptic splice site
Cyclic adenosine monophosphate (cAMP)
Cyclic AMP (cAMP)
Cyclic AMP receptor protein (CPR)
Cyclin: protein that accumulate continously throughout the cell cycle and are then destroyed by
proteolysis during mitosis
Cytoplasmic fertility gene
Cytoplasmic male sterility
Cytoplasmic protein synthesis
Cytotoxic T cell
Degree of dominance
Degrees of freedom
Denaturation(of DNA or RNA)变性（双链变单链）(见renaturation, or annealing)
Denaturing gradient gel electrophoresis
Depressed state: it is synonymous with induced when describing the normal state of a gene;
It has the same meaning as constitutive in describing the effect of mutation.
Dicentric chromosome: the product of fusing two chromosome fragments, each of which has a
Dideoxy sequencing method
Dihydrofolate reductase (DHFR)
Direct repeat: identical (or related) sequences present in two or more copies in the same
orientation in the same molecule of DNA; not necessarily adjacent.
Directed ampllification of minisatellite region DNA
Discontinuous replication: 不连续复制
Disjunction: the movement of members of a chromosome pair to opposite poles during cell
Displacement loop (D loop)
DNA adenine methylase
DNA amplification fingerprinting
DNA cloning vectors DNA
DNA-driven hybridization: involves the reaction of an excess of DNA with RNA
DNA fingerprinting 指纹法，指纹术，酶解图谱法
DNA repair genes
DNA uracyl glycosylase
Domain of a protein is a discrete continuous part of the amino acid sequence that can be equated
with a particular function.
Double minute chromosome (DM)
Down promoter mutations decrease the frequency of initiation of transcription.
Downstream: identifies sequences proceding farther in the direction of expression.
Duplicate-deficient chromosome complement
Duplication (doubling) 重迭
Early development: the period of a phage infection before the start of DNA replication
Ectopic expression: 异(常)位的expression of a gene in a tissue in which it is not usu. expressed
Elongation factor (EF): 延伸因子
Embryonic stem cells
End labeling: the addition of a radioactively labeled group to one end (5‘ or 3‘)of a DNA strand
Endocytic vesicles: membranous particles that transport proteins through endocytosis; also known
as clathrin-coated vesicles
Endocytosis: a process by which protein at the surface of the cell are internalized, being
transported into the cell within membranous vesicles.
End-product inhibition: the ability of a product of a metabolic pathway to inhibit the activity of an
enzyme that catalyzes an early step in the pathway.
Envelopes: surround some organelles (eg. Nucleus or mitochondrion) and consist of concentric
membranes, each membrane consisting of the usual lipid bilayer.
Enzyme (oxidoreductase氧化还原酶 transferase转移酶 lyase裂合酶 Hydrolase水解酶
Epigenetic changes: influence the phenotype without altering the genotype.
Episome: a plasmid able to integrate into bacterial DNA
Epistasis: a situation in which expression of one gene obscures the phenotypic effects of another
Equilibrium centrifugation in a density gradient
Equilibrium density-gradient centrifugation
Error free repair
Error prone repair
Escherichia coli ( E. Coli)
Essential gene: one whose deletion is lethal to the organism
Eubacteria: comprise the major line of prokaryotes
Euploid: having a balanced set or sets of chromosomes in any number
Evolutionary clock: is defined by the rate at which mutations accumulate in a given gene.
Excision repair: remove a single-stranded sequence of DNA containing damaged or mispaired
bases and replace it in the duplex by synthesizing a sequence complementary to the remaining strand.
Exit site (E site)
Exocytosis: the process of secreting proteins from a cell into the medium, by transport in
membranous vesicles from the endoplasmic reticulum, through the Golgi, to storage vesicles, and finally through the plasma membrane.
Expressed sequence tag
Expression vector: a cloning vector designed so that a coding sequence inserted at a particular site
will be transcribed and translated into protein.
Extranuclear gene: resides outside the nucleus in organelles
Facultative heterochromatin: the inert state of sequences that also exist in active copies
Fast component (of a reassociation reaction): the first to renature and contains highly repetitive
Fertility factor (F factor): a bacterial sex or fertility plasmid
Fidelity of replication
Figure eight: two circles of DNA linked together by a recombination event that has not yet been
Filter hybridization: is performed by incubating a denatured DNA preparation immobilized on a
nitrocellulose filter with a solution of radioactively labeled RNA or DNA.
Fine physical map
Fingerprint (of DNA): a pattern of polymorphic restriction fragments that differ between
Fingerprint (of a protein): the pattern of fragments generated by cleavage with an enzyme such as
First meiotic division
five prime end (5‘ end)
Fluidicity: a property of membranes. It indicates the ability of lipids to move laterally with in their
Fluorescence in situ hybridization (FISH) 荧光原位杂交（分子杂交）
Focus formation: the ability of transformed eukaryotic cells to grow in dense clusters, piled up on
Focus forming unit (ffu): a quantitative measure of focus formation.
Foldback DNA: consists of inverted repeats that have renatured by intrastrand reassociation of
Foot printing (footprinting): a technique for identifying the site on DNA bound by some protein
by virtue of the protection of bonds in this region against attack by nucleases.
forward mutation: inactive a wild-type gene
founder effect: the presence in a population of many individuals all with the same chromosome
derived from a single ancestor.
Frame shift (frameshift) mutation: change the frame in which triplets are translated into protein.
Free radical frequency of recombination
Full gene sequence
Gamete intrafallopian transfer(GIFT)
Gap (in DNA): the absence of one or more nucleotides in one strand of the duplex.
Gene amplification 基因扩增
Gene cluster: a group of adjacent genes that are identical or related
Gene controlling chromosome segregation
Gene conversion: alternation of one strand of a heteroduplex DNA to make it complementary with the other strand at any positions where there were mispaired bases.
Gene dosage: the number of copies of a particular gene in the genome.
Gene family 基因家族
Gene flow 基因流动（由于迁移和杂交繁殖致使基因在群体中的流动）
Gene library 基因库（一组克隆的DNA片段）
Gene mapping 基因定位：确定染色体上基因的相对位置
Gene of cellubiohydrolase
Gene pool (the totality of genes possessed by all the member of a population)基因库
Gene suppressing Ph activity
General transcription factor
Generalized linear models
Genetic code 遗传密码
Genetic engineering technologies
Genetic fine structure
Genetics of histocompatibility
Genomic DNA clones: sequences of the genome carried by a cloning vector
Genomic in situ hybridization
Genotype : the genetic constitution of an organism 基因型，遗传型
Genotype-environment association (G-E association)
Genotype-environment interaction (G-E interaction)
Germ line mosaicism
Golgi apparatus: individual stacks of membranes near the endoplasmic reticulum
G protein: guanine nucleotide-binding trimeric protein residing in the plasma membrane
Gratuitous inducer: resembles authentic inducer of transcription but are not substrates for the
Guide RNA (the RNA template present in telomerase)
Gynandromorph: a sexual mosaic
Gyrase (DNA): a type II topoisomerase of E. Coli with the ability to introduce negative supercoils
H1(H2, H3, H2A, H2B)histone
Hairpin: a double-helical region formed by base pairing between adjacent complementary
sequences in a single strand of RNA or DNA.
Haldane‘s mapping function
Hapten: a small molecule that acts as an antigen when conjugated to a protein
Heavy chain ( H chain)
Helicase: a protein that separates the strands of double-stranded DNA
Helix-loop-helix: a DNA-binding motif found in many regulatory proteins
Helper T cell
Helper virus: provides functions absent from a defective virus, enabling the latter to complete the
infective cycle during a mixed infection.
Hemizygote: a diploid individual that has lost its copy of a particular gene and which therefore has
only one single copy.
Hereditary genetic mutation heterozygosity
Heritability (broad-sense heritability and narrow-sense heritability)可遗传性，遗传力
Heteroduplex DNA: is generated by base pairing between complementary single strands derived
from the different parental duplex molecules.
Heteroduplex mobility assay (HMA)
Heterogeneous nuclear RNA (hnRNA): comprises transcripts of nuclear genes made by RNA
Heterokaryon: a cell containing two or more nuclei in a common cytoplasm 异核体
Heteromultimeric proteins: consist of nonidentical subunits coded by different genes
Highly repetitive DNA: the first component to reassociate and is equated with satellite DNA
Highly repetitive sequence
Holliday junction resolving enzyme
Holocentric chromsome (a chromosome with a diffuse centromere)
Homeobox: the conserved sequence that is part of the coding region of D. melanogaster homeotic
Homeotic gene: is defined by mutations that convert one body part into another; for example, an
insect leg may replace an antenna.
Homeotic selector gene
Homolog: chromosome carrying the same genetic loci
Homology (Homologies) 同种性，同源性
Homozygous embryo lethal
Hoogstein base pairing (an unusual type of base pairing)
Hot spot (Hotspot) : a site in a DNA molecule at which the mutation rate is much higher than the
rate for most other site
Housekeeping gene: a gene that is expressed at the same level in virtually all cells and whose
product participates in basic metabolic processes
Hox gene: clusters of mammalian gens containing homeoboxes
Human gene therapy
Human genome initiative
Human genome project
Hybrid-arrested translation: a technique that identifies the cDNA corresponding to an mRNA by
relying on the ability to base pair with the RNA in vitro to inhibit translation.
Hybridoma: a cell line produced by fusing a myeloma with a lymphocyte; it continues indefinitely
to express the immunoglobulins of both parents.
Hybrid dysgenesis: inability of certain strains of D Melanogaster to interbreed because the hybrids
Hybrid vigor (see heterosis)
Hybridization (also crossbreeding) 杂交，分子杂交，体细胞杂交，杂化:
the pairing of complementary RNA and DNA strands to give an RNA-DNA hybrid.
Hydrogen bond (a weak noncovalent linkage between two negatively charged atoms in which a
hydrogen atom is shared)
hydrolytic reaction: one in which a covalent bond is broken with the incorporation of a water
Hydrophilic groups: interact with water, so that hydropilic regions of protein or the faces of a lipid
bilayer reside in an aqueous environment
Hyperchromicity: the increase in opticla density that occurs when DNA is denatured.
Hypervariable regions (of an immunoglobulin): the parts of the variable region that show
maximum alternation when different antibodies are compared.
Identical twins (see monozygotic twins)
Identity by descent (Identity-by-descent): the condition in which two alleles are both replicas of a
single ancestral allele in the recent past
Ideogram: a diagrammatic representation of the G-banding pattern of a chromosome
Idling reaction: the production of pppGpp and ppGpp by ribosomes when an uncharged tRNA is
present in the A site.
Immunity ( a general term for resistance to a disease-causing agent after an initial infection)
Immortalization: the acquisition by a eukaryotic cell line of the ability to grow through an
indefinite number of divisions in culture.
In situ hybridization 原位杂交
In vitro 在活体外
In vitro culture
In vitro experiment
In vitro fertilization (IVF)
In vivo 在活体内
In vivo experiment
In vivo gene therapy
In vivo maturation (IVM)
Inborn error of metabolism
Incompatibility: inability of certein bacterial plasmids to coexist in the same cell
Induced mutation: results from the addition of a mutagen.
Inducer: a small molecule that triggers gene transcription by binding to a regulator protein
Inducible stable replication
Induction of prophage: excision from the host genome and entry into the lytic cycle as a result of
destruction of the lysogenic repressor.
Initiation: the beginning of protein synthesis
Initiation factor (IF in prokaryotes, eIF in eukaryotes)
Inosine: one of a number of unusual bases found in transfer RNA
Insertion sequence (IS): a small bacterial transposon that carries only the genes needed for its own
Integral membrane protein: a protein inserted into a membrane
Integration: insertion into a host genome as a region covalently linked on either side to the host
Integration host factor (IHF)
Interallelic complementation: the change in the properties of a heteromultimeric protein brought
about by the interaction of subunits coded by two different mutant alleles.
Interband: relatively dispersed region of polytene chromosomes that lie between the bands
Interchange 异位 (same as translocation)
Intercistronic region: the distance between the termination codon of one gene and the initiation
codon of the next gene
Inter-simple sequence repeat
Intra fallopian tube transfer
Intracistronic complementation 顺反子内互补
Intracytoplasmic sperm insertion (ICSI)
Intron (a noncoding DNA sequence in a gene that is transcribed but is then excised from the
primary transcript in forming a mature mRNA molecule; found primarily in eukaryotic cells. See also exon) 内含子
Inverse polymerase chain reaction 颠倒PCR
Inversion loop (loop structure formed by synapsis of homologous genes in a pair of chromosomes,
one of which contains an inversion)
Inverted repeat (IR)：颠倒重复
Inverted terminal repeats: short related or identical sequences present in reverse orientation at the
ends of some transposons
Isoaccepting tRNAs: represent the same amino acid
Isochromosome (a chromosome with two identical arms containing homologous genes)
Isotype: a group of closely related immunoglobulin chains
Joining (J) region
Karyotype: the entire chromosomal complement of a cell or species
Kilobase (Kb) 千碱基（1000个碱基对）
Kinase: an enzyme that phosphorylates to a substrate
Kinetochore (the cellular structure, formed in association with the centromere, to which the
spindle fibers become attached in cell division)
Kinetic complexity: the complexity of a DNA component measured by the kinetics of DNA
Kosambi‘s mapping function
Lac operon (the set of genes required to metabolize lactose in bacteria)
Lactose permease (an enzyme responsible for tansport of lactose from the environment into
Lampbrush chromosomes: the large meiotic chromosomes found in amphibian oocytes
Large single copy
Leader: nontranslated sequence at the 5‘ end of mRNA that procedes the initiation codon
Leader sequence: the region of an mRNA molecule form the 5‘ end to the beginning of the coding
Leaking mutation: allow some residual level of gene expression
Lethal locus: any gene in which a lethal mutation can be obtained
Li- Fraumeni syndrome
Library: a set of cloned fragments together representing the entire genome 基因库
Ligand: the molecule that binds to a specific receptor
Light chain (L chain)
Linkage quilibrium (the condition in which the alleles of different genes in a population are present in gametes in proportion to the product of the frequencies of the alleles.
Linker DNA: all DNA contained on a nucleosome in excess of the 146bp core DNA
Linker fragment: short synthetic duplex oligonucleotide
Linker scanner mutation: are introduced by recombining two DNA molecules in vitro at restriction
fragment added to the end of each
Linking number: number of times the two strands of a closed DNA duplex cross over each other
Liquid hybridization: a reaction between complementary nucleic acid strands performed in
Localized centromere ( the type of centromere organization found in most eukaryotic cells in
which the centromere is located in one small region of the chromosome)
Localized mutagenesis 定位诱变
Locus ( the site or position of a particular gene on a chromosome)(pl. Loci)(L.)位置，位点
Long terminal repeat (LTR): a sequence directly repeated at both ends of a retroviral DNA
Long-period interspersion: a pattern in the genome in which long stretches of moderately
repetitive and nonrepetitive DNA alternate
Loop: a sing-stranded region at the end of hairpin in RNA
Loss-of-function mutation (also called null mutation): a mutation that eliminates gene function
Lysis: breakage of a cell caused by rupture of its cell membrane and cell wall
Lysogen: clone of bacterial cells that have acquired a prophage
Lysogenic cycle: the phenomenon in which the DNA of an infecting phage becomes part of the
genetic material of the cell
Lytic cycle: the life cycle of a phage
Mad cow disease
Main band (of genomic DNA)
Major groove (in B-form DNA, the larger of two continuous indentations running along the
outside of the double helix)
Major histocompatibility complex (MHC)
Major histocompatibility locus
Masked mRNA (that cannot be translated until specific regulatory substances are available)
Maternal effect gene
Maternal inheritance (extranuclear inheritance of a trait through cytoplasmic factors or organelles
contributed by the female gamete) 母体遗传
Maternal sex ratio
Mating type locus (MAT)
Matingpype regulation (MAR)
Matrix attachment site (MAR)
Maxam-Gilbert method: a tehnique for determining the nucleotide sequence of DNA
Meiocyte (a germ cell that undergoes meiosis to yield gametes in animals or spores in plants)
Melting (of DNA): denaturation
Melting curve: a graph of the amount of denatured DNA present in a solution as a function of
Melting temperature (Tm)
Meristem: the mitotically active growing point of a plant tissue
Meristic trait: a trait in which the phenotype is determined by counting number of ears of eggs
Methylation: the modification of a protein or a DNA or RNA base by the addition of a methyl
Micrococcal nuclease: a nuclease that is isolated from a bacterium and that cleaves double-
stranded DNA without regard to sequence
Microsomes: fragmented pieces of endoplasmic reticulum associated with ribosomes
Microtubules: filaments consisting of dimers of tubulin
Microtubule associated proteins (MAPs)
Microtubule organizing center (MTOC)
Middle repetitive DNA sequence
Migration: movement of organisms among subpopulatons, or of molecules in electrophoresis)
Minor groove (the smaller of two continuous indentations running along the outside of the double helix)
Mitochondrial DNA (mtDNA)
Mitochondrial DNA sequence
Mitochondrial genetic disorder
Modification (of DNA or RNA): changes made to the nucleotides after their initial incorporation
into the polynucleotide chain
Mosaic: an organism composed of two or more genetically different types of cells
MPF : maturation or M phase-promoting factor
Multiple alleles: the presence in a population of more than two alleles of a gene
Multiple arbitrary amplicon profiling
Multiple cloning site (MCS)
Multiple gene line
Multivalent (an association of more than two homologous chromosomes resulting from synapsis
during meiosis in a polysomic or polyploid individual)
Mutagen (an agent that is capable of increasing the rate of mutation)
Negative chromatid interference
Neomorph: a mutation in which the mutant allele expresses either a novel gene product or a
mutant gene product that has a novel phenotypic effect
Neutral allele: an allele that has a negligible effect on the ability of the organism to survive and
Neutral substitution: changes of amino acids that do no affect activity
Nick: a single-strand break in a DNA molecule
Nicked circle: a circular DNA molecule containing one or more single-strand breaks
Nitrous acid: HNO2, a chemical mutagen
Noagenic hereditary mechanism
Nondisjunction: failure of chromosomes to separate and move to opposite poles of the division
spindle; the result is loss or gain of a chromosome.
Nonhistone chromosomal proteins
Nonparental ditype: an ascus containing two pairs of recombinant spores
Nontranscribed spacer: a region between transcription units
Northern blotting: a technique for transferring RNA
Nucleic acid hybridization
Nucleolar organizing region
Nucleolus (pl. Nucleoli)
Nucleoside: a purine or pyrimidine base covalently linked to a sugar.
Nucleus: the organelle, bounded by a membranous envelope
Null mutation: see loss-of-function mutation
Okazaki fragment: also called precursor fragment
Oligonucleotide site-directed mutagenesis
Oncogene: a gene that can initiate tumor formation
Open reading frame (ORF): in the coding strand of DNA or in mRNA, a region containing a series
of codons uninterrupted by stop codons and therefore capable of coding for a polypeptide chain.
Operator: a regulatory region in DNA that interacts with a specific repressor protein in controlling
the transcription of adjacent structural genes
Operon: a collection of adjacent structural genes regulated by an operator and a repressor.
Organelle: a membrane-bounded cytoplasmic structure that has a specialized function
Origin (ori): a sequence of DNA at which replication is initiated
Origin of replication (ori C): a DNA base sequence at which replication of a molecule is initiated
Orphans: isolated individual genes found in isolated locations, but related to members of a gene
P53 parental line
Pairing ( of chromosomes)
Pair-rule gene (any of a group of genes active early in Drosophila development that specifies the fates of alternating segments or parasegments. )
Palindrome: a sequence of DNA that is the same when one strand is read left to right or the other
is read right to left
Parasegment: developmental unit
Parental combination: alleles present in an offspring chromosome in the same combination as that
found in one of the parental chromosomes.
Parental ditype: an ascus containing two pairs of nonrecombinant spores
Partial gene sequence
Path in a pedigree: a closed loop in a pedigree
Pericentric inversion: an inversion that includes the centromere
Periodicity (of DNA): the number of base pairs per turn of the double helix
Permissive condition: an environmental condition in which the phenotype of a conditional
mutation is not expressed; contrasts with nonpermissive or restrictive condition
Phage: bacterial virus
Philadelphia chromosome: abnormal human chromosome 22, resulting from reciprocal
translocation and often associated with a type of leukemia
Phosphatase: an enzyme that removes phosphate groups from substrates
Phylogenetic tree: a diagram showing the genealogical relationships among a set of genes or
Physical map: a diagram showing the relative positions of physical landmarks in a DNA molecule
Plasma membrane: the continuous membrane defining the boundary of every cell
Plasmid: an automous self-replicating extrachromosomal circular DNA
Playback experiment: the retrieval of DNA that has hybridized with RNA to check that it is
nonrepetitive by a further reassociation reaction
Plectonemic winding: the interwinding of the two strands in the classical double helix of DNA
Pleiotropic effect: any phenotypic effect that is a secondary manifestation of a mutant gene多效
Point mutation: a mutation caused by the substitution, deletion, or addition of a single nucleotide
Polarity: the 5‘-to-3‘ orientation of a strand of nucleic acid
Pole cell: any of a group of cells, set off at the posterior end of the Drosophila embryo, from
which the germ cell are derived
Poly A RNA
Poly-A tail: the sequence of adenines added to the 3‘end of many eukaryotic mRNA molecules in
Polycistronic mRNA: coding regions representing more than one gene
Polygeneic inheritance: the determination of a trait by alleles of two or more genes
Polymerase chain reaction (PCR)
Polymorphic gene: a gene for which there is more than one relatively common allele in a
Polymorphism: simultaneous occurrence in the population of genomes showing allelic variations
Polyploid cell: having more than two sets of the haploid genome
Polyribosome: same as polysome
Polysome: a complex of two or more ribosomes associated with an mRNA molecule and actively
engaged in polypeptide synthesis
Population: a group of organisms of the same species
Position-effect variegation: mosaic phenotype(variegation) due to variation in the level of
expression of a gene in different cell lineages owing to its position in the genome
Positive chromatid interference
Precursor fragment : see Okazaki fragment
Predictive gene tests
Pribnow box: a base sequence in prokaryotic promoters to which RNA polymerase binds in an
early step of initiating transcription
Primary cell: the original unmodified RNA product corresponding to a transcription unit
Primer extension analysis
Prion protein: protein infectious agent; a protein that can transmit disease
Probe: a radioactive DNA or RNA molecule used in DNA-RNA or DNA-DNA hybridization
Procentriole: an immature centriole, formed in the vicinity of a mature centriole
Processing: a series of chemical reactions in which primary RNA transcripts are converted into
mature mRNA, rRNA, or tRNA molecules or in which polypeptide chains are converted into finished proteins
Programmed cell death
Promoter: a region of DNA involved in binding of RNA polymerase to initiate transcription
Promoter mutation: a mutation that increases or decreases the ability of a promoter to initiate
Promoter recognition: the first step in transcription
Proofreading function: see editing function
Prophage induction: activation of a prophage to undergo the lytic cycle
Proteolytic reactions: comprise the hydrolysis of peptide bonds in protein
Proto-oncogene: the normal counterparts in the eukaryotic genome to the oncogenes carried by
Provirus: a duplex DNA sequence in the eukaryotic chromosome corresponding to the genome of
an RNA retrovirus
PUC 19 library
Puff: expansion of a band of a polytene chromosome associated with the synthesis of RNA at some loci in the band
Pulse-field gel electrophoresis
Quantitative trait locus (QTL): a locus segregating for alleles that have different measurable
effects on the expression of a quantitative trait
Quaternary structure (of a protein): its multimeric constitution
Quick-stop dna mutants (of E. Coli): cease replication immediately when the temperature is up to
Random genetic drift
Random spore analysis
Randomly amplified polymorphic DNA (RAPD)
Rational drug design
Reassociation of DNA: describes the pairing of complementary single strands to form a double
Recessive: an allele or the corresponding phenotypic trait, expressed only in homozygotes
Reciprocal translocation: interchange of parts between nonhomologous chromosomes
Recombinant DNA molecule
Recombinant DNA technologies
Recombinant inbred (RI)
Recombinant substitution line
Recombination activation (Rac)
Recombination nodules (nodes): are dense objects present on the synaptonemal complex
Recruitment: the process in which a transcriptional activator protein interacts with one or more
components of the transcription complex and attracts it to the promoter
Redundancy: the feature of the genetic code in which an amino acid corresponds to more than one
codon; also called degeneracy
Relative fitness: fitness of a genotype expressed as a proportion of the fitness of another genotype
Relaxed mutants (of E. Coli) : do not display the stringent response to starvation for amino acids
Relaxed replication control: ability of some plasmids to continue replicating after bacteria cease
Release factor: termination factor
Repair associated division inhibitor (RADI)
Repair synthesis: the enzymatic filling of a gap in a DNA molecule at the site of excision of
a damaged DNA segment
Repetitive sequence: a DNA sequence present more than once per haploid genome
Replication: see DNA replication
Replication fork: the region in which nucleotides are added to growing strands
Replication slippage: the process in which the number of copies of a small tandem repeat can
increase or decrease during replication
Replicon: a DNA molecule that has a replication origin
Reporter gene: a gene whose expression can be monitored
Repression: a regulatory process in which a gene is temporarily rendered unable to be expressed
Resolvation site (res)
Restriction enzyme cutting site
Restriction fragment length polymorphism (RFLP)
Restriction landmark genomic scanning
Retroposon: a transposon that mobilizes via an RNA form; the DNA element is transcribed into
RNA, and then reverse-transcribed into DNA
Retroregulation: the ability of a sequence down stream to regulate translationof an mRNA
Retrovirus: one of a class of RNA animal viruses that cause the synthesis of DNA complementary
to their RNA genomes on infection
Reverse genetics: procedure in which mutations are deliberately produced in cloned genes and
introduced back into cells or the germ line of an orgnaism.
Reverse mutation: a mutation that undoes the effect of a preceding mutation
Ribonucleic acid (RNA)
Ribosomal RNA (rRNA)
Ribosome-binding site (also called Shine-Dalgarno sequence)
Right splicing junction: boundary between the right end of an intron and the left end of the
RNA-driven hybridization reaction
RNase (RNAase): any emzyme that cleaves RNA 核糖核酸酶
Salvage pathway: a minor source of deoxythymidine triphosphate for DNA synthesis that uses the enzyme thymidine kinase (TK) )
Scaffold: a protein-containing material in chromosomes
Sdr (stable DNA replication)
Second meiotic division
Selected marker (a genetic mutation that allows growth in selective medium)
Selection pressure (the tendency of natural or artificial selection to change allele frequency)
Selectively neutral mutation
Sequence characterised amplified region
Sequence tagged microsatellite
Sequence-tagged site (STS)
Simple sequence DNA: equals satellite DNA
Simple sequence repeats
Sin: suppression of initiation defect
Single primer amplification reaction
Single strand assimilation
Single stranded conformational polymorphism( SSCP)
Single strand exchange
Single tandem repeat polymorphism (STRP)
Single-strand binding protein
Single-stranded DNA (a DNA molecule that consists of a single polynucleotide chain)
Sister chromatids (chromatids produced by replication of a single chromosome)
Site specific recombination
Slow-stop dna mutants
Small nuclear RNA (snRNA)
Small nuclear ribonucleoprotein (snRNP)
Small rebonucleoprotein particles
Small single copy
Somatic cell gene therapy
Somatic cell genetic mutation
Somatic cell genetics
Somatic cell nuclear transfer
SOS repair (an inducible, error-prone system for repair of DNA damage in E.coli.)
Southern blot (a nucleic acid hybridization method)
Species: genetically, a group of actually or potentially inbreeding organisms that is reproductively
isolated from other such groups
Spheroplast: a bacterial or yeast cell whose wall has been largely or entirely removed
Spindle: a structure composed of fibrous proteins on which chromosomes align furing metaphase
and move during anaphase
Splice acceptor: the 5‘ end of an exon
Splice donor: the 3‘ end of an exon
Spliceosome: an RNA-protein particle in the nucleus in which introns are removed from RNA
Sporophyte: the diploid, spore-forming generation in plants
Stem: base-paired segment of a hairpin
Strain distribution patter (SDP)
Streptolydigins: inhibit the elongation of transcription by bacterial RNA polymerase
Substrate: a substance acted on by an enzyme
Supercoiling: coiling of double-stranded DNA in which strain caused by overwinding or
underwinding of the duplex makes the double helix itself twist; a supercoiled circle is also called a twisted circle or a superhelix.
Suppressed: the same as uninducible
Suppressor mutation: a mutation that partially or completely restores the function impaired by
another mutation at a different site in the same gene (intragenic suppression) or in a different gene (intergenic suppression)
Suppressor tRNA: usually, a tRNA molecule capable of translating a stop codon by inserting an
amino acid in its place, but a few suppressor tRNAs replace one amino acid with another.
Synapsis: the pairing of homologous chromosomes or chromosome regions in zygotene of the first
Synaptonemal complex: a complex protein structure that forms between synapsed homologous
chromosomes in the pachytene substage of the first meiotic prophase.
Synaptonemal complex damage
Syntenic: genetic loci lie on the same chromosome
Synteny: the presence of two different genes on the same chromosome.
Synteny group: a group of genes present in a single chromosome in two or more species
Tandem duplication: a pair of identical or closely related DNA sequences that are adjacent and in
the same orientation.
Tandem repeat sequences
Taster: one who has the inherited ability to taste the substance phenylthiocarbamide
TATA binding protein (TBP): a protein that binds to the TATA motif in the promoter region of a
TATA box: the base sequence 5‘-TATA-3‘ in the DNA of a promoter.
Temperate phage: a phage capable of both a lysogenic and a lytic cycle.
Test-cross (testcross): a cross between a heterozygote and a recessive homozygote
Testis-determining factor (TDF): genetic element on the mammalian Y chromosome that
Tetrad: the four chromatids that make up a pair of homologous chromosomes in meiotic prophase
I and metaphase I; also the four haploid products of a single meiosis.
Tetrad analysis: a method for the analysis of linkage and recombination using the four haploid
products of single meiotic divisions.
Tetraploida cell or organism with four complete sets of chromosomes
Tetratype: an ascus containing spores of four different genotypes
Thermal gel gradient electrophoresis (Tgge)
Thermophile: an organism that normally lives at an unusually high temperature.
θreplication: bidirectional replication of a circular DNA molecule, starting from a single origin of
30-nm fiber: the level of compaction of eukaryotic chromatin resulting from coiling of the
extended, nucleosome-bound DNA fiber.
Three-point cross: cross in which three genes are segregating
Thymine: a nitrogenous pyrimidine base found in DNA
Thymine dimer: see pyrimidine dimer
Topoisomerase: an enzyme that introduces or eliminates either underwinding or overwinding of
Totipotent cell: a cell capable of differentiation into a complete organism. The zygote is totipotent.
Trans configuration: the arrangement in linked inheritance in which a genotype heterozygous for
two mutant sites has received one of the mutant sites from each parent.
Transcriptonal activator protein
Transcription start site
Transduction: the carrying of genetic information from one bacterium to another by a phage.
Transfer RNA (tRNA)
Trans heterozygote : see trans configuration
Transition mutation: a mutation resulting from the substitution of one purine for another purine or that of one pyrimidine for another pyrimidine.
Translation: the process by which the amino acid sequence of a polypeptide is synthesized on a
ribosome according to the nucleotide sequence of an mRNA molecule.
Transposable element: a DNA sequence capable of moving(transposing) from one location to
another in a genome.
Transposase: protein necessary for transposition.
Transposition: the movement of a transposable element.
Transposon (Tn): a transposable element that contains bacterial genes
Transposon tagging: insertion of a transposable element that contains a genetic marker into a gene
Transverse transmission of genetic material
Transversion mutation: a mutation resulting from the substitution of a purine for a pyrimidine or
that of a pyrimidine for a purine.
Trinucleotide repeat: a tandemly repeated sequence of three nucleotides
Triplet code: a code in which each codon consists of three bases.
Triplicaton: the presence of three copies of a DNA sequence that is ordinarily present only once.
Triploid: a cell or organism with three complete sets of chromosomes.
Trisomic : a diploid organism with an extra copy of one of the chromosomes.
True-breeding: a strain, breed, or variety of organism that yields progeny like itself; homozygous
Truncation point: in artificial selection, the value of the phenotype that determines which
organisms will be retained for breeding and which will be culled.
Uncharged tRNA: a tRNA molecule that lacks an amino acid
Uncovering: the expression of a recissive allele present in a region of a structurally normal
chromosome in which the homologous chromosome has a deletion.
Underwound DNA: a DNA molecule whose strands are untwisted somewhat; hence, some of its
bases are unpaired.
Unequal crossing-over: crossing-over between nonallelic copies of duplicated or other repetitive
Unidentified reading frame (URF)
Unique sequence: a DNA sequence that is present in only one copy per haploid genome, in contrast with repetitive sequences
Unscheduled DNA synthesis
Uracil(U): a nitrogenous pyrimidine base found in RNA
Variable expressivity: differences in the severity of expression of a particular genotype.
Variable-number tandem-repeat (variable number of tandem repeats ) (VNTR): any region of the
genome that, among the members of a population, is highly polymorphic in the number of
tandem repeats of a short nucleotide sequence
Variable region (V region)
Variation of constitutive heterochromatin
Variegation: mottled or mosaic expression
Vector: a DNA molecule, capable of replication, into which a gene or DNA segment is inserted by
recombinant DNA techniques; a cloning vehicle
Viability: the probability of survival to reproductive age.
Viral oncogene: V-oncogene (V-onc)
Virulent phage: a phage or virus capable only of a lytic cycle; contrast with temperate phage.
Von Hippel-Lindau disease: hereditary disease marked by tumors in the retina, brain, other parts of
the central nervous system, and various organs throughout the body.
Wild-type (wildtype): the most common phenotype or genotype in a natural population
Wobble: the acceptable pairing of several possible bases in an anticodon with the base present in
the third position of a codon.
X chromosome: a chromosome that plays a role in sex determination and that is present in two
copies in the homogametic sex and in one copy in the heterogametic sex.
Xeroderma pigmentosum: an inherited defect in the repair of ultraviolet-light damage to DNA,
associated with extreme sensitivity to sunlight and multiple skin cancers.
X-linked inheritance: the pattern of hereditary transmission of genes located in the X
chromosome; usually evident from the production of nonidentical classes of progeny from reciprocal crosses.
X-linked recessive disorder
Yeast artificial chromosome (YAC)
Z-form DNA: one of the unusual three-dimensional structures of duplex DNA in which the helix
Zero time-binding DNA
Zinc finger: a structural motif, found in many DNA-binding proteins, in which finger-like
projections entrap a zinc ion.
Zygotene: the substage of meiotic phrophase I in which homologous chromosomes synapse.
Zygotic gene: any of a group of genes that control early development through their expression in