Explaining of genetics nouns一、Explain the following terms and concepts.1、heredity;（遗传）transmission of traits from one generation to another2、transmission genetics;（传递遗传学）is the brand dealing with the transmission of genes and genetic traits from generation to generation,and how genes recombine3、centromeres; （着丝点）each chromosome often has a constriction along its length4、zygote;（合子）the cell produced by the fusion of male are female gametes5、autosomes; （常染色体）chromosomes other than sex chromosome6、sister chromatid; （姐妹染色单体）a chromatud denved from replication of one chromosome during interphase of the cell cycle7、chromatin; （染色质）the mixture of DNA and protein8、semiconservative replication;（半保留复制）a model of DNA replication in which a double-stranded molecule replocates in such a way that the daughter moleculars are composed of one parental(dd)and one nemly synthesized serand9、the replication fork; （复制叉）the region where the helix unwinds and new DNA10、replicon; （复制子）DNA replicated from a single origin11、codon; （密码子）the DNA sequence of a gene is divided into a series of units of three bases12、degeneracy; （简并）the number of codons is greater,all of the amino acids,with the exception of methionine and typtophan,are encodoned by more that one codon13、hereditary traits; （遗传性状）the characteristics of an individual that one transmitted from one generation to another14、Genotype; （基因型）the genetic constitution of an organism15、phenotype; （表现型）is the observable properties(structural and functional)of organism produced by the interaction between its genotype and the environment16、pure-breeding lines; （纯种品系）this refers to organisms which have been inbred for many generations in which a certain phenotype remains the same17、dominance;（显性）in hybrids between two individuals with different phenotypes only ine phenotype may be observed18、testcross; （测交）is a cross of an individual of unknown genetype (usually expressing the dominant phenotype)with a known homozygous recessive individual in order to determine the unknown genetype19、the dihybrid cross;（双因子杂交）a cross involving two pairs of contrasting traits20、complete dominance; （完全显性）is the phenoment in which one alleles is dominant to another,so that the neterozygote(F1)is the same as that of the homozygous dominant 21、incomplete dominance; （不完全显性）expression of heterozygous(F1)phenotype which is distinct from and often intermediate to that of either parent22、multiple alleles; （复等位基因）three or more alleles of the same gene23、epistasis; （上位作用）is a from of gene interaction in which one gene masks the phenotypic expression of another24、linkage; （连锁）is the tendency of for alleles of two or more genes to be passed together from one generation to the next25、recombination frequency;（重组率）is the ratio of recombinant gametes to all the gametes produced in meiosis26、coupling phase; （相引组）the two dominant alleles are on one homolog and the two recessive alleles are on the other homolog,an arrangement27、repulsion phase; （相斥组）each homolog carries the dominant allele of one gene and the recessive allele of the other gene,an arrangement28、incomplete linkage; （不完全连锁）o ccasional separation of two genes on the same chromosome by a recombinational event29、crossing over; （交换）thw exchange of chromosomal material (parts of chromosomal arms)between homologous chromosomes by breakage and reunion30、genetic map; （遗传图）a replesentation of the genetic distance separating nonalleic gene loci in a linkage structure31、two-point testcross; （两点测验）a test involving two gened within a relatinely short section of the chromosome32、three-point testcross; （三点测验）a test involving three genes within a relatively short section of the chromosome33、sex chromosome; （性染色体）is a chromosome such as X or Y in hurnans ,which is involved in sex determinate34、sex-limited triaits（限性性状）in some cases,the expression of a specific phenotype is absolutely limited to one sexsex-influenced traits;（性别影响性状）means that the same phenotype will occur in both sexes but is more common in one35、spontaneous mutations （自发突变）are these that just happen in natureinduced mutations; （诱发突变）that reault from the influence of any artificial factor36、gametic mutations （配子诱变）a mutation event occurring in gametes or gamete-forming tissuessomatic mutations; （细胞诱变）a mutation event occurring in a somatic cell37、forward mutations （正突变）a mutationed change from a wild-type allele to a mutation allele, in general,A-areverse mutations; （反突变）a mutation change from a mutant allele back to a wild-type allele, in general, a-A38、point mutation; （真突变）a mutation that can be mopped to a single locus ,at the molecular level,a mutation that results in the substitution of one nucleotide for another 39、transition; （转换）a mutation event in which one purine is replaced by anpther or are pyrimidine is replaced by another40、transversion; （颠换）a mutational event in which a purine is replaced by a pyrimidine or a primidine is replaced by a purine41、missense mutations; （错义突变）these point mutations involve the alteration of a single base which changes a codon such that the encoded amino acid id altered42、nonsense mutations; （无义突变）these are point mutations that charge a codon for an amino acid a termination codon43、silent mutations ;（沉默突变）mutations many occour at the third base of a codon and ,due to the degeneracy of the genetic code,the amino acid will not be altered44、frameshift mutations; （移码突变）is a mutational event leading to the insertion ordeletion of one or more bases in a gene,shifting the codon reading frame in all codons following the mutational site45、transposable element; （转座因子）a genetic element of chromosomes of both prokaryotes and eukaryotes that has the capacity to mobilize itself and move from one location to another in the genome46、deletion;（缺失）a deletion is a chromosome mutation in which part of a chromosome is missing47、duplication; （重复）A chromosomed aberration in which a segment of the chromosomeB repeated48、inversion; （倒位）is a type of chromosomal aberration in which a segment of a chromosome is turn around 180 within a chromosome49、Robertsonian fusion;（罗伯孙融合）two telecentric chromosome or acro centric chromosomes, may fuse at the centromeres to give one metacentric or submetacentrec chromosome,reducing the number of chromosomes50、karyotypes; （核型）a complete set of all the metaphase chromosomes ina cell51、nullisomy; （缺体）describes an individual with a chromosomal aberration in which both members of a chromosome are missing.the cell is 2n-252、monosomy; （单体）an aneuploid conditive in which one member of a chromosome pair is missing 2n-153、trisomy; （三体）an aneuploid condition in which there are three copies of a particular chromosome instead of two copies 2n+154、tetrasomy; （四体）invlives an extra chromosome pair ,resulting in the presence of four copies of one particular chromosome and two copies of other chromosomes2n+255、autopolyploidy （同源多倍体）polyploidy involving more than two chromosomes sets of the same speciesallopolyploidy; （异源多倍体）polyploidy involving two or more genetically distinct sets of chromosomes56、qualitative trait （质量性状）traits such as these,withonly a few distinct phenotypes,area called discontinuous traits ,or qualitative traitsquantitative trait; （数量性状）traits with a continuous distribution of phenotypes are called continuous traits or quantitative traits57、Heterosis;（杂种优势）the superiority of a hererozygote over either homozygote for one or more characters58、virulent phages （烈性噬菌体）phages that undergo lytie infection are called virulent phagestemperate phages; （温和噬菌体）phages that undergo lysogenic infection are said to be temperate59、tansformation; （转化）it is possible to transfer DNA extracted from one bacterial culture to recipient in vitro .This is a process as transformation60、conjugation; （接合）a process in which there is a unidirectional transfer of genetic information through direct celluar contract between a clonor bacterice cell and a recipient bacterial cell61、F+ factor：the bacteria that contain the F plasmidF- factor：that bacteria that lack the plasmidHfr bacteria,：bacteria with integrated F plasmid are referced to HfrF' factor：the F plasmid is sometimes known as the F' factor62、transduction; （转导）under certain conditions bacteria phages can facilitate the transfer of genes between bacteria,the process is known as transduction63、operon; （操纵子）a genetic unit that consists of one or more structural genes whose expressions are negulated together by operator-regulator peotein interactives, plus the operator region itself and the promoter64、cytoplasmic inheritance;（胞质遗传）transmission of traits by genetic information contained in cytoplasmic organelles such as mitochondria and chloroplasts is known as this65、cytoplasmic-nuclear male sterility （雄性质核不育性）is controlled by both cytoplasmic genes and nuclear genesnuclear male sterility; （雄性核不育性）is mostly controlled by a single nuclear recessive gene ,but it may also be controlled by several genes,can be restored by the dominant gene contasting66、maternal effects; （母性影响）the phenotype in an indicidual that is established by the maternal nuclear genome,as the result of mRNA and /or proteins that are deposited in the occyty prior to fertilization67、population; （群体）is a groupo of individuals from the same species that lives in the same geographic area, and that actually or potentially interbreeds68、allele frequencies （等位基因频率）the frequency of an allele(A) in a population is the number of A alleles divided by the total number of alleles of that gene locusgenotype frequencies; （基因型频率）we count the number of individuals with one particular genotype and divided this number by the total number of individuals in the population 69、migration （迁移）migration occurs when individuals more between the populations genetic drift; （遗传漂变）random variation in allele frequency from generation to generation70、genetic species, （遗传学种）the genetic definition of a species is a set of actudlly or potentially interbreeding organisms,and sharing a common gene poolmorphological species （形态学种）all members of a species share a set of physicalcharacteristics which can distinguish them from members of other species ecological species （生态学种）each species uses a particular set of resources ,a niche,from that environment,and they do this most efficiently in a particular set of conditions or habitat71、Genome （染色体组）the complement of genetic information in a chromosome set.72、homologous chromosomes （同源染色体）in diploid organisms,the members of a chromosome pair that contain the same genes and that pair at meiosis are called homologous chromosomes73、bivalents （二价体）the bivalents lie across the equator of the cell74、complementary base pairing （碱基互补配对）two bonds from between A and T and three between G and C ,thus G-C bonds are stronger than A-T bonds,The way in which thebases from pairs between the two DNA strands is known as it75、Intergenic DNA: （基因间DNA）the genes are very dispersed and are separated from each other by sequences that do not appear to contain useful information76、template strand （模板链）only one of the two strands of the DNA double helix carriesan RNA molecule of a polypeptide77、Introns（内含子）one of the more surprising features of genes is that in higher organisma the coding information are separated by sequences that do not contain useful informationexons （外显子）one of the more surprising features of genes is that in higher organisms the coding information is usually split into a series of segments of DNA sequence78、Nucleosomes （核小体）are the basic building blocks of chromstin structure cinsisr ofa core of histone around which DNA is79、Euchromatin. （常染色体）it is a chromatin that stains lightly.It is uncoiled during interphase but becomes condensed during mitosis80、Heterochromatin （异染色体）It is chromatin that stains darkly is genetically inactive,either because it contains no genes or because the genes it does contain cannot be expressed81、constitutive heterochromatin （组成型异染色体）same chromatin is hetero chromatic in all tissues and all stages of developmentfacultative heterochromatin （兼性异染色体）some regions of chromatin exist in either the heterochromatic or euchromatic state82、synonymous codons. （同义密码子）codons which specify the same amino acid83、The central dogma （中心法则）the biological information in a DNA molecule is contained in its base sequence and states that the infoemation is transferred from DNA to RNA to protein84、Complete dominance（完全显性）is the phenotype in which one alleles is domoninant to another ,so that theheterozygote(F1)is the same as that of the homozygous dominant85、co-dominance （共显性）the heterozygote(F1)exhibits the phenotypes of both homozygotes(parents)86、lethal allele （致死等位基因）an allele that results in the death of an organism87、the coefficient of coincidence（并发系统）the observed frequency of double cross-overs divided by the expected frequency of double cross-overs. S=0.58[0,1]88、Hemogametic （同型配子的）means that with respect to sex chromosomes gametes are all identical89、gene mutations . （基因突变）mutations in the sequences of genes at the level of the base pair90、Mutation rate （突变率）is the number of occurrence of a kind of 、mutation expressed as the proportion of cells or individuals in a population91、Wild-type （野生型）an organism that displays the usual phenotypr for that species92、Mutant （突变型）an organism whose usual phenotype has changed as the result of a mutation93、Mutagen （诱变剂）any physical or chemical agent that significantly increases the frequency of mutational events a spontaneous mutation rate94、Insertion sequences （插入序列）is the simplest transposable element found in prokaryetes. These DNA segments are relatively short, not exceeding 2000bp.The first insertion sequence to be characterized in E.coil,IS1,is 768bp long ,IS2,3,4and 5 are about 1250~1400bp long95、composite transposons （复合型转座子）have a central region containing genes flanked on both sides by IS elementsnoncomposite transposons （非复合型转座子）exemplified by the 4957bpTn3,also contain genes such as those for drug resistance they do not terminate with IS elements96、Terminal deletions （顶端缺失）invdue a single break,then the fragment with a centromere obtaining a new telomere97、Interstitial deletions （中间缺失）involve by rejoining of the ends of the flanking pieces98、paracentric inversion （臂内倒位）if the centromere isnot part of the inverted segment pericentric inversion （臂间倒位）if the centromere is part of the inverted segment99、inversion heterozygotes （倒位杂合体）organisims with one inverted chromosome and one noninverted homdog100、Translocation （易位）the movement of a chromosomal segment to a new location in the genome101、Simple translocation （简单易位）a chromosomal aberration in which a segment within a chromosome move into an nontromologous chromosome102、Reciprocal translocation （相互易位）a chromosomal aberration in which a nonhomologous chromosomes exchange parts103、Robertsonian fusion（Robertsonian融合）Fusion of two acrocentric chromosomes at the centromere.104、euploid （整倍体）when an organism or cell has one complete set of chromosomes or an exact multiple of complete sets ,that organism or cell105、aneuploid （非整倍体）chromosome mutations resulting in variations in the number of individual chromosomes produce106、Polyploidy（多倍性）is the state of having more than two complete sets of chromosomes107、Autoallopolyploids（同源异源多倍体）indicate that a polyploidy individual has more than two basic genomes ,and at least one basic genome is present more than two times108、H eritability : （遗传力）the proportion of phenotypic variation in a population attributable to genetic factors109、Broad sense heritability （广义遗传力）is the ratio of the genetic variance to the total phenotypic variance,therefore110、Narrow sense heritability （狭义遗传力）the proportion of the phenotypic variance that results from additive genetic variance111、Inbreeding（近交）is mating between relatives,or in extreme cases,self-fertilization by hermaphrodites112、episomes（附加体）we refer to plasmids that can exist in these two states113、sexduction . （性导）F primes are capable of moving to F-bacteria and in so doing bring their complement of host genes with them114、cotransduction （共转导）two genes that are close enough on the bacterial chromosome can be simultaneously transduced,a process called contransduction115、Specialized transduction （特殊性转导）genetic transfer of only specific host genes by transducing phages116、gene pool（基因库）is the total of all alleles possessed by reproductive members of a population117、the Hardy-weinberg law （哈迪温伯特规律）the principle that both gene and genotype frequencies will remain in equilibrium in an infinitely large population in the absence of mutation,migration,selection,and nonrandom mating118、Natural selection （自然选择）is the constraint that natural conditions put on the size of populations,forcing individuals of the same species to compete for limited119、Stabilizing selection .（稳定化选择）tends to favor intermediate types,with both extreme phenotypes being selection against120、Directional selection （定向选择）favors individuals with characteristics at one end of the range found in the population121、Disruptive selection （分裂选择）is selection against intermediates and for both phenotypic extreams.It can be viewed as the opposite of stadilizing selection because the intermediate types are selected against122、Random mating （随机交配）all the gametes unite to form zygotes,the proportion of the genotypes will be equal to p2,2pq and q2 ,and the frequency of the alleles un these zygotes will remain p and q123、Premating isolation mechanisms（交配前隔离机制）prevebt interbreeding and zygote formation124、Postmating isolation mechanisms （交配后隔离机制）reduce the viability and/or fertility of hybrids produced by mating between members of two species125、H ybrid inviability （杂种不存活）hybrids zygote are inviable or have reduced viability 126、Hybrid sterility （杂种不育性）one or both sexes of the F1 hybrids are sterile or have reduced fertility127、H ybrid breakdown （杂种败落）F1 hybrids are normal,vigorous,and fertile but F2 or backcross hybrids are inviable,sterile,or have reduced viability or fertility128、Speciation （物种形成）is the process of forming two or more species from a single 129、Allopatric speciation （异地种形成）process of speciation associated with geographic isolation130、Sympatric speciation （同地种形成）process of secration involving population that inhabit,at least in part,the same geographic range131、N egative control: （负调控）if there exists the repressor represses the transcription of the structural genes,this mechanism is known as negative control132、Positive control（正调控）a regulation mechanism in which the transcription of the structural genes is incluced by an inducer133、trans-acting factors （反式作用因子）the transcription factors are synthesized in the cytoplasm of the cell but exert their effects in the nucleus134、Plasmon（细胞质基因组）all the genetic materials present in organelles and cytoplasmic particles are known as these135、Population genetics（群体遗传学）population genetics is the quantitative study of the frequencies of alleles and genotypesin populations,wheras evolution is the change in thoes frequencies over time。