CG (or CpG) island --- Any region of the genome containing an unusually high concentration of the dinucleotide sequence 5’-CG-3’. Often associated with promoters of genes, in particular housekeeping genes.
CG（或CpG）岛：含双核苷酸序列5’-CG-3’较多的区域。通常与基因（尤其是持家基因）的启动子有关。
CGH --- See comparative genome hybridization.
CGH：参见比较基因组杂交。
Chain termination mutation --- A mutation that generates a stop codon, thus preventing further synthesis of the polypeptide chain.
链终止突变：形成终止密码子的突变，因而终止了多肽链的继续合成。
Checkpoint --- Positions in the cell cycle, usually at the junction between the G1 and S or the G2 and M stages, at which the cell determines whether to proceed to the next stage of the cycle.
检查点：细胞周期的监控机制，通常在G1 期与S 期，或G2期与 M期之间，决定细胞是否进入下一个周期。
Chemical individuality --- A term coined by Archibald Garrod to describe the naturally occurring differences in the genetic and biochemical makeup of each individual.
药品个体化：由Archibald Garrod提出，形容每位个体遗传和生化构成的不同。
Chiasma --- Literally, a cross. The term refers to the crossing of chromatid strands of homologous chromosomes, seen at the diplotene of the first meiotic division. Chiasmata are thought to be evidence of interchange of chromosomal material (crossovers) between members of a chromosome pair.
交叉：在减数分裂前期的双线期，联会复合体中非姐妹染色单体之间发生了互换，互换的连接点称为交叉。
Chimera --- An individual composed of cells derived from two genetically different zygotes. In humans, blood group chimeras result from exchange of hematopoietic stem cells by dizygotic twins in utero; dispermic chimeras, which are very rare, result from fusion of two zygotes into one individual. Chimerism is also an inevitable result of transplantation.
【异源】嵌合体：由来自不同基因型的合子演变而来的两个或多个不同的细胞系混合构成的个体。在人类，二卵双生子在子宫中交换造血干细胞，而导致血型嵌合体；双精嵌合体十分罕见，两个受精卵融合为一个个体所致。移植必定导致嵌合现象。
Chorionic villus sampling (CVS) --- A procedure used for prenatal diagnosis at 8 to 10 weeks’
绒膜绒毛取样（CVS）：妊娠８～１０周时进行产前诊断的一种方法。在超声指导下，通过宫颈或腹壁取得绒膜绒毛，以进行胎儿组织分析。
Chromatids --- The two parallel strands of chromatin, connected at the centromere, that constitute a chromosome after DNA synthesis.
染色单体：染色体复制后仍由同一个着丝粒连在一起的两条子染色体。
Chromatin --- The complex of DNA and proteins of which chromosomes are composed. See also nucleosome.
染色质：ＤＮＡ和组蛋白的复合物。参见核小体。
Chromosomal satellite --- A small mass of chromatin containing genes for ribosomal RNA, at the end of the short arm of each chromatid of an acrocentric chromosome; not to be confused with satellite DNA.
染色体随体：染色质的一小部分，含有核糖体ＲＮＡ基因，位于近端着丝粒染色体的短臂染色质末端；勿与卫星ＤＮＡ混淆。
Chromosome --- One of the threadlike structures in the cell nucleus; consists of chromatin and carries genetic information (DNA).
染色体：细胞核中的线形结构；由染色质构成，携带遗传信息（ＤＮＡ）。
Chromosome disorder --- A clinical condition caused by an abnormal chromosome constitution in which there is duplication, loss, or rearrangement of chromosomal material.
染色体病：染色体结构和数目异常引起的遗传病，包括染色体的重复、丢失和重排等。
Chromosome mutation --- A change in the genetic material at the chromosome level.
染色体突变：染色体水平的遗传物质改变。
Chromosome painting probe --- A multilocus probe designed for fluorescence in situ hybridization (FISH) that hybridizes to only one particular chromosome or chromosome arm.
染色体涂染探针：用于荧光原位杂交（FISH）的多基因座探针，只与某一染色体或染色体臂杂交。
Chromosome segregation --- The separation of chromosomes or chromatids in cell division so that each daughter cell gets an equal number of chromosomes.
染色体分离：细胞分裂过程中染色体或染色质的分离，使得每个子细胞获得相同数目的染色体。
Chromosome spread --- The chromosomes of a dividing cell as seen under the microscope in metaphase or prometaphase.
染色体铺展：显微镜下的中期或前期分裂细胞的染色体形态。
Cis --- Refers to the relationship between two sequences that are on the same chromosome, literally meaning “on the near side of.”
顺式：指两条序列位于同一条染色体上。相当于反式。
Clinical heterogeneity --- The term describing the occurrence of clinically different phenotypes from mutations in the same gene.
临床异质性：同一基因突变的临床表型差异现象。
Clinical utility --- In reference to a clinical laboratory test, the ability of that test to improve the medical care that an individual receives.
临床效用：指一种临床实验室检测方法对改善个体医疗状况的能力。
Clinical validity --- In reference to a clinical laboratory test, the ability of that test to detect the disease that the test was designed to detect.
临床效力：指一种临床实验室检测方法正确检测出疾病的能力。
Clonal evolution --- The multistep process of successive genetic changes that occur in a developing tumor cell population.
克隆演变：肿瘤发展中的细胞群相继发生遗传改变的多步骤过程。
Clone --- 1. A cell line derived by mitosis from a single ancestral diploid cell; in embryology, a cell lineage in which the cells have remained geographically close to each other. 2. In molecular biology, a recombinant DNA molecule containing a gene or other DNA sequence of interest. Also, the act of generating such a cell line or clone.
克隆：１.源自单个二倍体祖细胞有丝分裂而得到的细胞系；在胚胎学中，指位置邻近的细胞组成的细胞系。２.在分子生物学中，指含目标基因或ＤＮＡ序列的重组ＤＮＡ分子。也指产生这种细胞系或克隆的过程。
Cloning, molecular --- Transfer of a DNA sequence into a single cell of a microorganism, followed by culture of the microorganism to produce large quantities of the DNA sample for analysis.
分子克隆：将ＤＮＡ序列转移到微生物单细胞中，然后培养微生物，以产生大量ＤＮＡ样本用以分析。
CNP --- See copy number variant.
CNP：参见拷贝数目变异体。
CNV --- See copy number variant.
CNV：参见拷贝数目变异体。
Coding strand --- In double-stranded DNA, the strand that has the same 5’ to 3’
编码链：双链ＤＮＡ中，５′至３′端与mRNA相同的那条链（Ｔ在mRNA中为Ｕ）。编码链不被ＲＮＡ合成连转录。参见有义链。
Codominant --- If both alleles of a pair are expressed in the heterozygous state, then the alleles (or the traits determined by them, or both) are codominant.
共显性：若在杂合子中，一对等位基因都表达，则这对等位基因（或其决定的性状）为共显性。
Codon --- A triplet of three bases in a DNA or RNA molecule, specifying a single amino acid.
密码子：ＤＮＡ或ＲＮＡ分子上三个碱基组成的三联体，决定一种氨基酸。
Coefficient of inbreeding (F) --- The probability that an individual homozygous at a locus received both alleles from one ancestor (i.e., the alleles are identical by descent).
近交系数（F）：度量个体近交程度的参数，即1个纯合子的2个等位基因遗传自同一个祖先的概率（等位基因为相同的血统）。
Cofactor-responsive disease --- A genetic disease in which a specific biochemical abnormality affecting a single mutant protein (usually an enzyme) is corrected by the administration of pharmacological amounts of the specific cofactor of the mutant protein (e.g., vitamin B6-responsive homocystinuria).
辅因子反应性疾病：因某个特异的生化异常影响到一种单一蛋白（通常为一种酶）突变而引起的一类遗传病。可以通过补充该突变蛋白的辅因子而得到纠正（如VB6反应性同型胱氨酸尿症）。
Colinearity --- The parallel relationship between the base sequence of the DNA of a gene (or the RNA transcribed from it) and the amino acid sequence of the corresponding polypeptide.
共线性：基因DNA序列（或其从转录的RNA）和翻译产物中氨基酸之间的次序一致。
Commitment --- The transition of an embryonic cell from pluripotency to its particular fate.
定型：限定细胞按某一特定命运发育的过程。
Comparative genome hybridization (CGH) --- A fluorescence hybridization technique used to compare two different DNA samples with respect to their relative content of a particular DNA segment or segments. CGH can be used with fluorescence in situ hybridization of metaphase chromosomes (FISH) or with hybridization to large numbers of DNA fragments fixed to a solid support (CGH array).
比较基因组杂交（CGH）：一种荧光杂交技术，用于比较两个不同的DNA样本的某个DNA片段或序列的相对含量。可与荧光原位杂交（FISH）结合，或与固定在介质上的DNA片段相杂交（CGH array）。
Complementarity --- The complementary nature of base pairing in DNA.
互补性：DNA中碱基对的互补特性
Complementary DNA (cDNA) --- DNA synthesized from a messenger RNA template, through the action of the enzyme reverse transcriptase. See genomic DNA for comparison.
互补DNA（cDNA）：以mRNA为模板经反转录得到的DNA分子。参见比较基因组DNA。
Complementation --- The ability of cells from patients with two different genetic defects to correct one another, thus demonstrating that the defects are not identical. The complementation may be intergenic or intragenic.
互补作用：在一个二倍体细胞里，两个亲本的基因组各自补足另一个基因组所缺失功能的过程。分为基因间互补和基因内互补。
Complex inheritance --- A pattern of inheritance that is not mendelian. A trait with complex inheritance usually results from alleles at more than one locus interacting with environmental factors.
复杂遗传：一种非孟德尔遗传方式。复杂遗传的性状通常由几个基因与环境因素相互作用而形成。
Compound (compound heterozygote) --- An individual, or a genotype, with two different mutant alleles at the same locus. Not to be confused with homozygote, in which the two mutant alleles are identical.
复合（复合杂合子）：在两条同源染色体的同一基因座上有两个不同的突变等位基因的个体（或基因型）。注意纯合子是2个相同的等位基因，勿混淆。
Concordance --- Describes a pair of relatives in which (1) both members of the pair have a certain qualitative trait or (2) both members have values of a quantitative trait that are similar in magnitude. See discordance.
一致性：用于形容两个亲属（1）都具有某种质量性状；（2）都具有某种数量性状。参见不一致性。
Conditional probability --- 1. In Bayesian analysis, this is the chance of an observed outcome given that a consultand has a particular genotype. The product of the prior and conditional probabilities is the joint probability. 2. More generally, a synonym for Bayesian analysis.
条件概率：1.为Bayesian定理的一个基本概念，指一个随机事件在另一个事件已发生的条件下的概率。2.常为Bayesian分析的代名词。
Confined placental mosaicism --- Mosaicism in a chorionic villus sampling (CVS) specimen obtained from the placenta that is not present in the fetus itself.
胎盘特异性嵌合体：绒膜绒毛取样（CVS）检查中的嵌合体，胎儿本身非嵌合体。
Congenital --- Present at birth; not necessarily genetic.
先天性：出生即带的；并非都是遗传性的。
Consanguineous --- Related by descent from a common ancestor (the noun is consanguinity).
近亲：亲缘关系较近的个体。
Consensus sequence --- In genes or proteins, an idealized sequence in which each base or amino acid residue represents the one most frequently found at that position when many actual sequences are compared; for example, the consensus sequence for splice donor or acceptor sites.
共有序列：基因和蛋白质中反复出现且很少有改变的序列。如剪接供位和受位的共有序列。
Consultand --- In genetic counseling, anyone who consults a genetic counselor for genetic information.
先询者：在遗传咨询中，咨询遗传师以寻求遗传方面的信息的人。
Contiguous gene syndrome --- A syndrome resulting from a microdeletion of chromosomal DNA extending over two or more contiguous loci. Also called segmental aneusomy.
邻接基因综合征：染色体的微小缺失引起的一类疾病。这类缺失往往涉及两个以上的邻接基因座。又称片段异倍性。
Copy number variant (CNV) --- A variation in DNA sequence defined by the presence or absence of a segment of DNA, ranging from 200 bp to 2 Mb. Copy number variants may also have alleles that are tandem duplications of two, three, four, or more copies of a DNA segment. If a variant has an allele frequency >1%, it is referred to as a copy number polymorphism (CNP).
拷贝数目变异体（CNV）：某200 bp~2 Mb 的DNA片段或存在或不存在的一种变异。也指DNA片段的串联重复。若这种变异体的频率超过1%，则称为拷贝数目多态性（CNP）。
Cordocentesis --- A procedure used in prenatal diagnosis to obtain a sample of fetal blood directly from the placenta.
脐穿刺：从胎盘直接获得胎儿血进行产前诊断的一种方法。
Correlation --- A statistical tool applied to a set of paired measurements. A positive correlation exists when the larger the first measurement in the pair is, the larger the second measurement of the pair is. A negative correlation is the opposite, that is, the larger the first measurement, the smaller the second.
相关：用相关系数来计量的两个或几个随机变量协同变化的程度。当变量间呈现同一方向的变化趋势时称为“正相关”，反之则称为“负相关”。
Correlation coefficient (r) --- A measure of correlation that varies from 1 for perfect positive correlation to -1 for perfect negative correlation; it is 0 when there is no correlation between pairs of measurements.
相关系数（r）：度量两个随机变量间关联程度的量。当相关系数小于0时，为负相关；大于0时，为正相关；等于0时，为不相关。
Coupling --- Describes the phase of two alleles at two different but syntenic loci, in which one allele at one of the loci is on the same chromosome as the allele at the second locus. See phase and repulsion.
互引相 ：描述2个同线性基因座上的2个等位基因排列关系的术语。如一个显性基因与另一个基因座的显性基因连锁时其杂合体的排列方式为AB/ab。
Crossover, crossing over --- The reciprocal exchange of segments between chromatids of homologous chromosomes, a characteristic of prophase of the first meiotic division. See also recombination. Unequal crossing over between misaligned chromatids can lead to duplication of the involved segment on one chromatid and deletion on the other and is a frequent cause of mutation.
交换：减数分裂过程中同源染色体因断裂和重接产生遗传物质间的局部互换。参见重组。
Cryptic splice site --- A DNA sequence similar to the consensus splice site but not normally used. It is used when the normal splice site is altered by mutation or when a mutation in the cryptic site increases its use by the splicing apparatus. May be in a coding or a noncoding sequence.
隐蔽剪接位点：与剪接位点序列相似，但一般不进行剪接的位置。突变可能使其进行剪接。可位于编码区或非编码区。
Cytogenetics --- The study of chromosomes.
细胞遗传学：研究染色体的学科。
Cytotrophoblast --- The fetal cells of the chorionic villi that are sampled for karyotyping and DNA analysis.
细胞滋养层：绒毛膜的胎儿细胞，可用于核型分析和DNA检测。
Daughter chromosomes --- The two individual chromosomes formed when a single chromosome composed of paired chromatids separates at the centromere in anaphase of cell division.
子染色体：姐妹染色单体从着丝粒处分开后形成的2条新染色体。