Microarray --- Miniaturized wafer (“chip”) made of glass, plastic, or silicon onto which a large number of different nucleic acids have been individually spotted. See also CGH, expression profile.
微阵列：点阵分布有大量核苷酸的微小芯片。参见CGH，表达谱。
Microdeletion --- A chromosomal deletion that is too small to be seen under the microscope. See also contiguous gene syndrome.
微小缺失：无法用显微镜观察到的较小的染色体缺失。参见邻接基因综合征。
Microsatellite marker --- See short tandem repeat polymorphism (STRP).
微卫星标记 ：参见短串联重复多态性（STRP）。
Minisatellite --- See VNTR.
小卫星：参见VNTR。
Missense mutation --- A mutation that changes a codon specific for one amino acid to specify another amino acid.
错义突变：突变成编码另一种氨基酸的密码子。
Mitochondrial bottleneck --- A step in oogenesis in which only a small sample of the total number of mitochondria in an oocyte precursor is passed on to daughter cells, thereby allowing significant variation in the proportions of mutant and wild-type mitochondria inherited by the daughter cells.
线粒体瓶颈：卵母细胞中的线粒体只有小部分能够遗传至子细胞，造成突变线粒体和野生型线粒体比例显著变化的现象。
Mitochondrial DNA (mtDNA) --- The DNA in the circular chromosome of the mitochondria. Mitochondrial DNA is present in many copies per cell, is maternally inherited, and evolves 5 to 10 times as rapidly as genomic DNA.
线粒体DNA（mtDNA）：存在于线粒体中的环状DNA。每个细胞有多份线粒体DNA拷贝，呈母系遗传，比基因组DNA进化快5～10倍。
Mitochondrial inheritance --- The inheritance of a trait encoded in the mitochondrial genome. Because the mitochondrial genome is strictly maternally inherited, mitochondrial inheritance occurs solely through the female line.
线粒体遗传：由线粒体基因组编码的性状的遗传。
Mitosis --- The process of ordinary cell division, resulting in the formation of two cells genetically identical to the parent cell.
有丝分裂：一种普通的细胞分裂形式，形成两个遗传信息与母细胞一致的子细胞。
Model-based linkage analysis --- Linkage analysis that relies on assuming a particular mode of inheritance to infer when crossovers have occurred between two loci. Also referred to as parametric linkage analysis.
模型连锁分析：先假设一种特异的遗传模式，再得出两个基因座间何时发生交换的连锁分析法。参见参数连锁分析。
Model-free linkage analysis --- Linkage analysis that makes no assumptions as to the mode of inheritance. This form of analysis relies on determining whether the extent of allele sharing at any loci among related individuals who either do or do not share a disease or trait deviates significantly from what would be expected by chance alone. See affected pedigree member method. Also referred to as nonparametric linkage analysis.
非模型连锁分析：不假设遗传模式的连锁分析法。主要分析亲属间共享的等位基因与疾病表型之间是否有连锁关系。参见患病家系成员法。又称非参数连锁分析。
Modifier gene --- A gene that alters the phenotype associated with mutations in a nonallelic gene.
修饰基因：通过相互作用而影响到其它基因表型效应的基因。
Monosomy --- A chromosome constitution in which one member of a chromosome pair is missing, as in 45,X Turner syndrome.
单体：某对染色体少了一条。如45,X （Turner综合征）。
Monozygotic (MZ) twins --- Twins derived from a single zygote and thus genetically identical. Also termed identical twins.
同卵双生：同一个受精卵在胚胎发育早期，卵裂球割裂为两团细胞而发育成的双生子。又称单卵双生。
Morphogen --- A substance produced during development in a localized region of the organism that diffuses out to form a concentration gradient and directs cells into two or more specific developmental pathways, depending on its concentration.
形态发生素：在发育过程中，特定区域形成的浓度梯度可决定特定细胞类型发育的命运。这些物质即形态发生素。
Morphogenesis --- The process whereby changes in cell shape, adhesion, movement, and number lead to three-dimensional structure.
形态发生：在发育过程中形成一个器官或结构的过程。
Mosaic --- An individual or tissue with at least two cell lines differing in genotype or karyotype, derived from a single zygote; not to be confused with chimera.
【同源】嵌合体：在遗传上不同的细胞类型或组织所组成的生物体。
Mosaic development --- Embryological development in which different regions of the embryo develop independently from surrounding regions. See regulative development.
镶嵌发育：胚胎的各区域从周围区域独立发育起来的胚胎发育阶段，参见调整式发育。
Multifactorial inheritance --- The type of non-mendelian inheritance shown by traits that are determined by a combination of multiple factors, genetic and environmental. Also termed complex inheritance.
多因子遗传：非孟德尔遗传方式。性状由多个因素决定，包括遗传和环境因style="LINE-HEIGHT: normal; MARGIN-BOTTOM: 0pt" class=Glossdef>Multiplex --- A pedigree in which there is more than one case of a particular disorder.
多重：有一个以上的特定疾病案例的家系。
Multiplex testing --- A laboratory method that allows many different tests to be performed simultaneously on the same sample.
多重检测：在同一个样本中同时进行多个检测的实验方法。
Mutagen --- An agent that increases the spontaneous mutation rate by causing changes in DNA.
诱变剂：能使细胞或生物个体的突变频率显著高于自发突变水平的物理或化学因子。
Mutant --- A gene that has been altered by mutation; also used to refer to a nonhuman organism carrying a mutant gene.
突变体：存在突变的基因；也指携带突变基因的个体。
Mutation --- Any permanent heritable change in the sequence of genomic DNA.
突变：基因组DNA中永久性的可遗传的序列改变。
Mutation rate (m) --- The frequency of mutation at a given locus, expressed as mutations per locus per gamete (or per generation, which is the same).
突变率（m）：在一定时间内，每一世代发生的基因突变总数或特定基因座上的突变数。
Negative predictive value --- With respect to a clinical test for a disease, the extent to which testing negative indicates that one does not have or will not develop the disease.
阴性预测值：临床检测的衡量度。即检测结果为阴性时，则个体不会患病的程度。
Neoplasia --- An abnormal growth produced by imbalance between normal cellular proliferation and normal cellular attrition. May be benign or malignant (cancer).
瘤形成：正常细胞增殖和死亡之间失衡而导致的一种异常增长。瘤可能为良性或恶性。
Noncoding strand --- See antisense strand of DNA.
非编码链：参见DNA反义链。
Nondisjunction --- The failure of two members of a chromosome pair to disjoin during meiosis I, or of two chromatids of a chromosome to disjoin during meiosis II or mitosis, so that both pass to one daughter cell and the other daughter cell receives neither.
不分离：减数分裂（I或II）中同源染色体互不分开的现象。
Nonsense mutation --- A single-base substitution in DNA resulting in a chain-termination codon.
无义突变：编码氨基酸的密码子突变为终止密码子，使肽链合成中断。
Northern blotting --- A technique analogous to Southern blotting, for detection of RNA molecules by hybridization to a complementary DNA probe.
RNA印迹法：RNA从电泳凝胶转移到固相介质上，然后与互补的核苷酸序列探针杂交的操作过程。
Novel property mutation --- A mutation that confers a new property on the protein.
新特性突变：赋予蛋白质新性质的突变。
Nuchal translucency --- An ultrasonographic finding of an echo-free space between the skin line and the soft tissue overlying the cervical spine in the subcutaneous tissue of the fetal neck. Associated with fetal aneuploidy.
颈项透明层：超声检查中，胎儿颈椎水平矢状切面皮肤至皮下软组织之间的无回声区。
Nucleic acid hybridization --- See hybridization.
核酸杂交：参见杂交。
Nucleosome --- The primary structural unit of chromatin, consisting of 146 base pairs of DNA wrapped twice around a core of eight histone molecules.
核小体：染色质的基本组成单位，146个碱基对的DNA缠绕在组蛋白八聚体分子的核心上。
Nucleotide --- A molecule composed of a nitrogenous base, a 5-carbon sugar, and a phosphate group. A nucleic acid is a polymer of many nucleotides.
核苷酸：包括一个含氮碱基，一个5-碳糖，和一个磷酸基团的分子。核酸是核苷酸的多聚体
Null allele --- An allele that results either in the total absence of the gene product or in the total loss of function of the product.
无效等位基因：完全失去活性的等位基因。
Obligate heterozygote --- An individual who may be clinically unaffected but on the basis of pedigree analysis must carry a specific mutant allele.
肯定杂合子：遗传上已确认为携带特异的突变等位基因，但临床上还未发病的个体。
Odds --- A ratio of probabilities or risks. Often calculated as a ratio of the probability of an event’s occurring versus the probability of the event’s not occurring, as one way to assess the relative chance of the event. Odds can vary in value from 0 to infinity.
比值：概率或风险的比值。通常计算为某事件发生的概率与不发生的概率之比，以评估事件的相对发生几率。
Odds ratio --- A comparison of the odds that individuals who share a particular factor (e.g., a genotype, an environmental exposure, or a drug) will have a disease or trait versus the odds for individuals who lack the factor.
Affected Unaffected Total
Factor present a b a+b
Factor absent c d c+d
Total a+c b+d a+b+c+d
Among individuals in whom the factor is present, the odds of being affected =(a/b). Among individuals in whom the factor is absent, the odds of being affected =(c/d), and the odds ratio =(a/b)/(c/d)=ad/bc. [Strictly speaking, this definition of odds ratio is a disease odds ratio. A more traditional odds ratio used in epidemiology is an exposure odds ratio, which is a comparison of the odds that individuals affected with a particular disease were exposed to a particular factor =(a/c) versus the odds that unaffected individuals where exposed =(b/d), giving an odds ratio of (a/c)/(b/d). Note that both formulations result in the same ratio =ad/bc. Using a disease odds ratio formulation makes it easier to show arithmetically that a disease odds ratio approximates the relative risk ratio when the disease is rare (c << d and a << b)]. See relative risk.
比值比：某因素对某性状或患病的效应强度。通过比较疾病或性状组与正常对照组的基因型、环境接触因子或药物等特定的因素，得出相对的比值。具体计算方法如下：
患病（性状）对照 合计
携带某因素 a b a+b
不携带某因素 c d c+d
合计 a+c b+d a+b+c+d
患病组携带某因素的比例=(a/b)，患病组不携带某因素的比例=(c/d)，故比值比=(a/b)/(c/d)=ad/bc。严格地说，这是疾病的比值比，并非特定流行病学调查意义上的某个接触因素的比值比。详见正文。参见相对风险。
Oligonucleotide --- A short DNA molecule (usually 8 to 50 base pairs), synthesized for use as a probe or for use in the polymerase chain reaction.
寡核苷酸：用于探针或PCR的合成的短DNA分子（通常长8～50个碱基对）。
Oncogene --- A dominantly acting gene responsible for tumor development. Mutation, overexpression, or amplification of oncogenes in somatic cells may lead to neoplastic transformation. Contrast with proto-oncogene and with tumor-suppressor gene.
癌基因：能诱导所存在的细胞发生癌变的显性活动基因。体细胞癌基因的活化方式为突变、过表达和扩增。相对于原癌基因和肿瘤抑制基因。
Ontogeny --- The developmental history of an organism.
个体发生：从受精卵或生殖细胞发育为成体的整个过程。
Open reading frame --- The interval between the start and stop codons of a nucleotide sequence that encodes a protein.
可读框：自起始密码子到终止密码子之间的核苷酸三联体序列。
Orthologous --- Refers to genes in different species that are similar in DNA sequence and also encode proteins that have the same function—at least at the biochemical level—in each species. Orthologous genes originate from the same gene in a common ancestor. Contrast with paralogous.
种间同源基因：不同物种间序列相似的DNA ，编码功能相似的蛋白质。种间同源基因起源于同一祖先的同一个基因。相对于种内同源基因。
p --- 1. In cytogenetics, the short arm of a chromosome (from the French petit). 2. In population genetics, the frequency of the more common allele of a pair. 3. In biochemistry, abbreviation of protein (e.g., p53 is a 53-kD protein).
p：1.在细胞遗传学中，指染色体的短臂。2. 在群体遗传学中，指一对等位基因中较常见的那个等位基因的频率。3. 在生物化学中，为蛋白质的缩写。如p53 即为53-kD蛋白。
PACs (P1 artificial chromosomes) --- Vectors capable of cloning DNA inserts 100 to 300 kb in size, used in high-resolution mapping and gene sequencing.
P1噬菌体人工染色体：能够插入100～300kb DNA的克隆载体，用于高分辨率的制图和基因测序。
Painting probe --- See chromosome painting probe.
涂染探针：参见染色体涂染探针。
Paired domain --- A DNA-binding motif found in the members of a large class of mammalian transcription factors encoded by PAX genes. Named originally for the Drosophila paired gene in which it was first described.
成对域：一种DNA结合基序，属于由PAX基因编码的一类哺乳动物转录因子的一员。
Palindrome --- In molecular biology, a nucleotide sequence in which the 5？ to 3？
回文序列：单条核苷酸序列内以对称点为中心，两侧碱基互补的核心序列区域。常见于限制酶的作用位点。
Paralogous --- Refers to two or more genes in a single species that are similar in DNA sequence and are likely to encode proteins with similar and perhaps overlapping but not identical functions. Paralogous genes are likely to have originated from a common ancestral gene. Example, α- and β-globin genes.
种内同源基因 进化过程中，同一生物体中起源于同一祖先基因重叠的那些基因。如α-珠蛋白和β-珠蛋白基因。
Parental transmission bias --- A phenomenon seen with the inheritance of unstable repeat expansion mutations in which expansions of the repeat occur preferentially when the mutation is transmitted by one parent versus the other.
亲代遗传偏倚：不稳定重复扩增突变的遗传现象，由一方亲代遗传时才会出现这种重复扩增突变。
PCR --- See polymerase chain reaction.
PCR：参见聚合酶链反应。
Pedigree --- In medical genetics, a family history of a hereditary condition, or a diagram of a family history indicating the family members, their relationship to the proband, and their status with respect to a particular hereditary condition.
系谱：一个家族各世代成员数目、亲缘关系、特定基因和遗传标记在该家族内的传递、表达和分布的记载。
Penetrance --- The fraction of individuals with a genotype known to cause a disease who have any signs or symptoms of the disease. Contrast with expressivity.
外显率：在特定环境中，某一基因型显示预期表型的个体比率。相对于表现度。