Spectral karyotyping (SKY) --- A procedure that uses the fluorescence in situ hybridization (FISH) technique to stain each of the 24 human chromosomes distinctively.

图谱核型分析（SKY）：用荧光原位杂交（FISH）技术，对 24条人类染色体进行各自染色。

Splicing --- The splicing out of introns and splicing together of exons in the generation of mature mRNA from the primary transcript.

剪接：从前体RNA分子上除去内含子序列使相邻外显子重新连接的机制。通过此过程形成成熟的RNA。

Sporadic --- In medical genetics, a disease that is not the result of inheritance of a disease-causing allele from a parent. Often the result of a new germline or somatic mutation.

散发：在医学遗传学中，指非双亲的遗传因素引起的病例。通常源于种系的新突变或体细胞突变。

Stem cell --- A type of cell capable both of self-renewal and of proliferation and differentiation.

干细胞：一类未分化的、具有无限自我更新繁殖能力的细胞。

Stop codon --- See termination codon.

终止密码子：参见termination codon。

Stratification --- The situation in which a population contains a number of subgroups whose members have not freely and randomly mated with the members of other subgroups.

分群婚配：大群体包含一些小群体，其中的个体不能与其他小群体个体进行交配的现象。

Structural gene --- A gene coding for any RNA or protein product.

结构基因：任何编码RNA或蛋白质的基因。

Structural protein --- A protein that serves a structural role in the body, such as collagen.

结构蛋白：体内起结构性作用的蛋白质。如胶原蛋白。

Submetacentric --- A type of chromosome with arms of different lengths.

近中着丝粒染色体：着丝粒的位置介于中部和端部之间的染色体。

Synapsis --- Close pairing of homologous chromosomes in prophase of the first meiotic division.

联会：减数分裂中两条同源染色体纵向间的配对。

Syndrome --- A characteristic pattern of anomalies, presumed to be causally related.

综合征：同时出现的一组症候群。

Synpolydactyly --- A birth defect of the hands and feet characterized by extra digits and the fusion of adjoining digits.

并指/趾多指/趾畸形：一种手足出生缺陷，表现为多指（趾）或并指（趾）。

Synteny --- The physical presence together on the same chromosome of two or more gene loci, whether or not they are close enough together for linkage to be demonstrated.

同线性：存在于同一条染色体上的2个或多个基因座。

Tag SNPs --- A select, minimal subset of all the SNPs in a genomic region, chosen because they are in linkage disequilibrium with one another in the population. Tag SNPs are useful because they form a minimum set of SNPs whose alleles constitute haplotypes capable of representing all the common haplotypes in that region. See HapMap.

标记SNP：群体中连锁不平衡的一组SNP。参见HapMap。

Tandem repeats --- Two or more copies of the same (or similar) DNA sequence arranged in a direct head-to-tail succession along a chromosome.

串联重复：首位相连的重复序列。

TATA box --- A consensus sequence in the promoter region of many genes that is located about 25 base pairs upstream from the start site of transcription and that determines the start site.

TATA框：基因启动子中的一段保守序列，通常位于转录起点上游25bp处。

T-cell antigen receptor (TCR) --- Genetically coded receptor on the surface of T lymphocytes that specifically recognizes antigen molecules.

T细胞抗原受体（TCR）：编码T淋巴细胞表面受体，特异识别抗原分子。

Telomerase --- A ribonucleoprotein reverse transcriptase that uses its own RNA template to add species-specific hexamers (such as TTAGGG in humans) to telomeres.

端粒酶：催化端粒中重复单元合成的一种核糖核蛋白酶。

Telomere --- The end of each chromosome arm. Human telomeres end with tandem copies of the sequence (TTAGGG)n, which is required for the proper replication of chromosome ends.

端粒：真核染色体两臂末端由特定DNA重复序列构成的结构，使正常染色体端部间不发生融合，保证每条染色体的完整性。人类的端粒具有末端串联重复序列(TTAGGG)n。

Telophase --- The stage of cell division that begins when the daughter chromosomes reach the poles of the dividing cell and that lasts until the two daughter cells take on the appearance of interphase cells.

末期：细胞有丝分裂或减数分裂过程中子染色体到达两极至完成胞质分裂的过程。

Teratogen --- An agent that produces congenital malformations or increases their incidence.

致畸剂：能够导致胚胎畸变的物理、化学或生物因子。

Termination codon --- One of the three codons (UAG, UAA, and UGA) that terminate synthesis of a polypeptide. Also called a stop codon. (See Table 3-1.)

终止密码子：终止多肽链合成的密码子（UAG、UAA和UGA）。英文又称stop codon，详见表3-1.

Tertiary structure --- Three-dimensional configuration.

三级结构：即三维构象。

Trans --- Refers to the relationship between two sequences located across from each other on the two homologous chromosomes, or to interactions between a protein and a chromosome locus. Literally means “across from.” Contrast with cis.

反式：非同一条染色体上的序列，或蛋白质与染色体基因座之间的关系。相对于顺式。

Transcription --- The synthesis of a single-stranded RNA molecule from a DNA template in the cell nucleus, catalyzed by RNA polymerase.

转录：DNA的遗传信息被拷贝成RNA的遗传信息的过程。

Transcription factor --- One of a large class of proteins that regulate transcription by forming large complexes with other transcription factors and RNA polymerase; these complexes then bind to regulatory regions of genes either to promote or to inhibit transcription.

转录因子：能识别启动子、增强子或特定序列而调控基因表达的蛋白质。

Transfer RNA (tRNA) --- See RNA.

转移RNA（tRNA）：参见RNA。

Transformation --- An in vitro phenomenon in which certain cell lines, such as cancer cells, are able to grow indefinitely in culture. More generally, the process in vivo by which a normal cell in a tissue becomes a cancerous cell.

转化：体外培养的真核细胞变为生长失控状态，类似于肿瘤细胞的生长。

Transition mutation --- Substitution of one purine for another purine or one pyrimidine for another pyrimidine.

转换突变：核酸序列中一种嘌呤（或嘧啶）被另一种嘌呤（或嘧啶）置换。

Translation --- The synthesis of a polypeptide from its mRNA template.

翻译：根据mRNA模板合成多肽链的过程。

Translocation --- The transfer of a segment of one chromosome to another chromosome. If two nonhomologous chromosomes exchange pieces, the translocation is reciprocal. See also Robertsonian translocation.

易位：一条染色体上的一个片段转接到染色体组中另一条染色体上。若是两条非同源染色体之间的交换，这种易位称为相互易位。参见罗伯逊易位。

Transversion --- A mutation caused by substitution of a purine for a pyrimidine or vice versa.

颠换：核酸序列中一种嘌呤（或嘧啶）被另一种嘧啶（或嘌呤）置换。

Triploid --- A cell with three copies of each chromosome, or an individual made up of such cells.

三倍体：有三套染色体组的细胞或个体。

Trisomy --- The state of having three representatives of a given chromosome instead of the usual pair, as in trisomy 21 (Down syndrome).

三体：二倍体中某一对同源染色体增加了一条染色体的细胞或个体。如21三体（Down综合征）。

tRNA --- Transfer RNA; see RNA.

tRNA ：转移RNA。参见RNA。

Tumor-suppressor gene --- A normal gene involved in the regulation of cell proliferation. Recessive mutations can lead to tumor development, as in the retinoblastoma gene or the p53 gene. Contrast with oncogene.

肿瘤抑制基因：抑制肿瘤发生的一种基因。隐性突变可导致肿瘤发生。常见的肿瘤抑制基因为Rb和p53。相对于癌基因。

Two-hit model --- The hypothesis that some forms of cancer can be initiated when both alleles of a tumor-suppressor gene become inactivated in the same cell.

两次突变假说：一种癌症发生的假说。认为一个细胞中的肿瘤抑制基因的2个等位基因都发生突变失活，则引发癌症。

Ultrasonography --- A technique in which high-frequency sound waves are used to examine internal body structures; useful in prenatal diagnosis.

超声检查法：利用超声波检查身体结构，以便发现异常；用于产前诊断。

Uniparental disomy --- The presence in the karyotype of two copies of a specific chromosome, both inherited from one parent, with no representative of that chromosome from the other parent. If both homologues of the parental pair are present, the situation is heterodisomy; if one parental homologue is present in duplicate, the situation is isodisomy. See Prader-Willi syndrome and Angelman syndrome in the text.

单亲二体：体细胞中的同源染色体均来自一个亲本的个体。若同源染色体来自双亲双方，则为异二体；若同源染色体仅来自一个亲本，则为同二体。参见正文的Prader-Willi综合征和Angelman综合征。

Unstable repeat expansion disorders --- Diseases that occur when a gene contains tandemly repeating units of a few nucleotides and the number of such units increases beyond a threshold and interferes with the expression or function of that gene. Most commonly, the nucleotide unit involved in the expansion contains three nucleotides (triplet repeat expansion), as with CAG in Huntington disease or CGG in fragile X syndrome.

不稳定重复扩增疾病：基因中包括几个核苷酸的串联重复单元，单元重复次数增加到阈值以上，影响基因功能，从而致病。以三核苷酸单元为常见（三联体重复扩增），如Huntington 舞蹈症的CAG、脆性X综合征的CGG。

Vector --- In molecular genetics, the DNA molecule into which a gene or DNA fragment has been cloned, capable of replicating in a specific host and thereby replicating the cloned DNA segment as well. Vectors include plasmids, bacteriophage lambda, cosmids, and both bacterial and yeast artificial chromosomes.

载体：在分子克隆中携带外源DNA的质粒、噬菌体或重组体。

VNTR (variable number of tandem repeats) --- A type of DNA polymorphism created by a tandem arrangement of multiple copies of short DNA sequences. Highly polymorphic, used in linkage studies and in DNA “fingerprinting” for paternity testing and forensic medicine.

VNTR（可变数目串联重复）：短重复单元串联重复而成的DNA序列。呈高度多态性，用于连锁分析和亲子、法医鉴定中的DNA“指纹”。

Western blotting --- A technique analogous to Southern blotting, used for detection of proteins, usually by immunological methods.

蛋白质印迹法：蛋白质分子从电泳凝胶转移到固相介质，然后用抗体进行免疫检测的技术。

Wild-type --- A term used to indicate the normal allele (often symbolized as +？) or the normal phenotype.

野生型：即正常等位基因或正常表型。

X;autosome translocation --- Reciprocal translocation between an X chromosome and an autosome.

X;常染色体易位：X-染色体与常染色体之间的相互易位。

X inactivation --- Inactivation of genes on one X chromosome in somatic cells of female mammals, occurring early in embryonic life, at about the time of implantation. See lyonization.

X失活：女性体细胞中的一条X-染色体上的基因失活的现象。发生在胚胎早期。参见莱昂化。

X linkage --- The distinctive inheritance pattern of alleles at loci on the X chromosome that do not undergo recombination (crossing over) during male meiosis.

X连锁：位于X染色体上的基因的遗传现象。

Y linkage --- Genes on the Y chromosome, or traits determined by such genes, are Y-linked.

Y连锁：位于Y染色体上的基因的遗传现象。

Zinc finger proteins --- One class of transcription factor proteins containing loop-shaped tandem repeating segments that bind zinc atoms.

锌指蛋白：一种转录因子，其分子内部由于锌指离子的存在而形成多肽链内部的折叠，呈手指状突起。

Zygosity --- The number of zygotes from which a multiple birth is derived. For example, twins may be either monozygotic (MZ) or dizygotic (DZ). To determine whether a certain pair of twins is MZ or DZ is to determine their zygosity.

卵性：多胎的受精卵的个数。例如，孪生子包括同卵双生或二卵双生。确定属于哪种双生子类型，就可确定其卵性。

Zygote --- A fertilized ovum.

受精卵：已受精的卵子。