Gene flow --- Gradual diffusion of genes from one population to another across a barrier. The barrier may be physical or cultural and may be breached by migration or mixing.

基因流：由于合子或配子的散布，基因从某一群体扩散到其它群体，从而引起等位基因频率改变的现象。

Gene map --- The characteristic arrangement of the genes on the chromosomes.

基因图：染色体上基因的特异排布。

Gene pool --- All the alleles present at a given locus or, more broadly, at all loci in the population.

基因库：某基因座或群体所有基因座上的所有等位基因的总和。

Gene therapy (gene transfer therapy) --- Treatment of a disease by introduction of DNA sequences that will have a therapeutic benefit.

基因治疗（转基因治疗）：将缺陷基因的野生型拷贝引入患者细胞内以治疗疾病的方法。

Genetic --- Determined by genes; not to be confused with congenital.

遗传性：由基因决定的，与先天性相区别。

Genetic code --- The 64 triplets of bases that specify the 20 amino acids found in proteins (see Table 3-1).

遗传密码：编码20种氨基酸和多肽链起始及终止的一套64个三联体密码子。

Genetic complementation --- The ability of one mutant allele at a locus to correct for the loss of function associated with another allele at the same or another locus, thus demonstrating that the mutations are not identical. See complementation.

遗传互补：野生型基因补偿突变型基因的缺陷使细胞表型恢复正常的现象。参见互补作用。

Genetic counseling --- The provision of information and assistance to affected individuals or family members at risk of a disorder that may be genetic, concerning the consequences of the disorder, the probability of developing or transmitting it, and the ways in which it may be prevented or ameliorated.

遗传咨询：为患者或其家属提供与遗传疾病相关的知识或信息的服务。

Genetic disorder --- A defect wholly or partly caused by a gene abnormality.

遗传病：基因异常而导致的疾病。

Genetic drift --- Random fluctuation of allele frequencies in small populations.

遗传漂变：在小群体中由于世代间配子的随机抽样造成的误差所导致的基因频率的随机波动。

Genetic epidemiology --- A branch of public health research concerned with characterizing and quantifying the influence of genetic variation in the population on the incidence, prevalence, and causation of disease.

遗传流行病学：研究基因及其变异和环境因素的相互作用与疾病发生、流行和控制之间关系的遗传学分支学科。

Genetic heterogeneity --- The production of the same or similar phenotypes by different genetic mechanisms. See allelic heterogeneity, clinical heterogeneity, locus heterogeneity.

遗传异质性：不同基因型决定相同表型的现象。参见等位基因异质性、临床异质性和基因座异质性。

Genetic lethal --- A mutant allele or genetically determined trait that leads to failure to reproduce, although not necessarily to death prior to reproduction.

遗传致死：突变等位基因或遗传突变决定的性状，导致不能生育。并非都在育龄前死亡。

Genetic load --- The sum total of death and disease caused by mutant genes.

遗传负荷：由突变基因引起的死亡和疾病的总和。

Genetic map --- The relative positions of the genes on the chromosomes, as shown by linkage analysis. See physical map for comparison.

遗传图：依据连锁分析所得重组值及其它方法确定连锁基因或遗传标记在染色体上的相对位置。勿与物理图混淆。

Genetic marker --- A locus that has readily classifiable alleles and can be used in genetic studies. It may be a gene or a restriction enzyme site or any characteristic of DNA that allows different versions of a locus (or its product) to be distinguished one from another and followed through families. See polymorphism.

遗传标记：可示踪染色体、染色体片段、基因等传递轨迹的一种遗传特性。遗传标记可以是一个基因，一个酶切位点，一个用以区分个体或追踪家系的基因座或其产物。参见多态性。

Genetic screening --- Testing on a population basis to identify individuals at risk of developing or of transmitting a specific disorder.

遗传筛选：从一个群体中鉴别和选择出某种所需的基因或基因型的过程。

Genocopy --- A genotype that determines a phenotype closely similar to that determined by a different genotype.

拟基因型：不同等位基因组成的类似的基因型产生相同表型。

Genome --- The complete DNA sequence, containing the entire genetic information, of a gamete, an individual, a population, or a species.

基因组：配子、个体、群体或物种的全部DNA序列，包括所有遗传信息。

Genomic DNA --- The chromosomal DNA sequence of a gene or segment of a gene, including the DNA sequence of noncoding as well as coding regions. Also, DNA that has been isolated directly from cells or chromosomes or the cloned copies of all or part of such DNA.

基因组DNA：一个基因或基因片段的染色体DNA序列，包括所有编码或非编码序列。也包括直接从细胞、染色体或该DNA的克隆拷贝上直接分离出来的DNA。

Genomic medicine --- The practice of medicine based on large-scale genomic information, such as expression profiling to characterize tumors or to define prognosis in cancer, genotyping of variants in genes involved in drug metabolism or action to determine an individual’s correct therapeutic dosage, or analysis of multiple protein biomarkers to monitor therapy or to provide predictive information in presymptomatic individuals.

基因组医学：基于大规模基因组信息的医疗。如根据表达谱来定性肿瘤或诊断癌症；对有关药物代谢的基因进行分型，决定个体的治疗剂量；分析蛋白生物标记，监测治疗进程，对症状前个体提供预见信息。

Genomics --- The field of genetics concerned with structural and functional studies of the genome.

基因组学：研究生物体基因组的组成、结构与功能的学科。

Genotype --- 1. The genetic constitution of an individual, as distinguished from the phenotype. 2. More specifically, the alleles present at one locus.

基因型：1.个体的遗传组成。2.一个基因座上的等位基因。

Germ layer --- One of three distinct layers of cells that arise in the inner cell mass, the ectoderm, mesoderm, and endoderm, each of which develops into a distinctly different tissue in the embryo.

胚层：胚胎发育到原肠胚时的细胞层，分为内胚层、中胚层、外胚层，各胚层将发育成一定的组织器官。

Germline --- The cell line from which gametes are derived.

种系：多细胞动物中能繁殖后代的一类细胞的总称。

Germline mosaicism --- In an individual, the presence of two or more genetically different types of germline cells, resulting from mutation during the proliferation and differentiation of the germline.

种系嵌合体：种系由不同基因型的细胞所构成的生物体。

Globin switching --- Change in expression of the various globin genes during ontogeny.

珠蛋白转换：个体发育中各种珠蛋白基因表达的改变。

Haploid --- The chromosome number of a normal gamete, with only one member of each chromosome pair. In humans, the haploid number is 23.

单倍体：正常配子的染色体数目，即每对染色体都只有一条。人类染色体的单倍体数目为23条。

Haploinsufficiency --- A cause of genetic disease in which the contribution from a normal allele is insufficient to prevent disease because of a loss-of-function mutation at the other allele.

单倍不足性：遗传病的原因之一，单倍的基因剂量不足以维持正常功能。

Haplotype --- A group of alleles in coupling at closely linked loci, usually inherited as a unit.

单体型：HapMap --- A set of haplotypes, defined by tag SNPs, distributed throughout the genome, used for association studies.

单体型图：由标签SNP确定的所有单体型，散布在整个基因组中。用于连锁分析。

Hardy-Weinberg law --- The law that relates allele frequency to genotype frequency, used in population genetics to determine allele frequency and heterozygote frequency when the incidence of a disorder is known.

Hardy-Weinberg定律：在一个没有突变、选择和迁移的遗传漂变的无限大的随机交配群体中，一对等位基因在常染色体上遗传时，无论群体起始基因频率如何，只要经过一代的随机交配，群体的基因型频率和基因频率即达到平衡状态。

Hemizygous --- A term for the genotype of an individual with only one representative of a chromosome or chromosome segment, rather than the usual two; refers especially to X-linked genes in the male but also applies to genes on any chromosome segment that is deleted on the homologous chromosome.

半合子：只存在于一条同源染色体上，而不是成对出现的基因；如男性的X-连锁基因，也指一条同源染色体缺失时的基因。

Heritability (h2) --- The fraction of total phenotypic variance of a quantitative trait that is due to genotypic differences. May be viewed as a statistical estimate of the hereditary contribution to a quantitative trait.

遗传率（h2）：遗传因素在多基因遗传病发生因素中所占的比例。

Heterochromatin --- Chromatin that stains darkly throughout the cell cycle, even in interphase. Generally thought to be late replicating and genetically inactive. Satellite DNA in regions such as centromeres, acrocentric short arms, and 1qh, 9qh, 16qh, and Yqh constitute constitutive hetero­chromatin, whereas the chromatin of the inactive X chromosome is referred to as facultative hetero­chromatin. Contrast with euchromatin.

异染色质：间期核内染色质丝折叠压缩程度高，处于凝聚状态，染料着色深的那部分染色质。富含重复DNA序列，复制延迟，一般无转录活性。位于卫星DNA区的着丝粒、近端着丝粒短臂以及1qh、9qh、16qh和Yqh属于功能性异染色质，而失活的X染色质属于兼性异染色质。相当于常染色质。

Heterodisomy --- See uniparental disomy.

异二体：参见单亲二体。

Heterogeneity --- See allelic heterogeneity, clinical heterogeneity, genetic heterogeneity, locus heterogeneity.

异质性：参见等位基因异质性、临床异质性、遗传异质性和基因座异质性。 ---

Heteromorphism --- A normal morphological or staining variant of a chromosome.

异态性：染色体正常形态的微小变异。 ---

Heteroplasmy --- The presence of more than one type of mitochondrial DNA in the mitochondria of a single individual. Contrast with homoplasmy.

杂质： 一个细胞或个体含有多种线粒体DNA的现象。相当于纯质。

Heteroploid --- Any chromosome number other than the normal.

异倍体：染色体组中缺少或额外增加一条或若干条完整的染色体的细胞或二倍体生物。

Heterozygote (heterozygous) --- An individual or genotype with two different alleles at a given locus on a pair of homologous chromosomes.

杂合子（杂合性）：在二倍体生物中，一对同源染色体上特定的基因座上有两个不同的等位基因的个体或细胞。

Histocompatibility --- A host will accept a particular graft only if it is histocompatible—that is, if the graft contains no antigens that the host lacks.

组织相容性：只有组织相容性的移植物才可移植入宿主——即移植物无宿主缺乏的抗原。

Histone code --- A pattern of histone variants and post-translational modifications that determine specific properties of chromatin associated with epigenetics and differential gene expression.

组蛋白密码：组蛋白的变异和翻译后修饰的型，决定特定的染色质性质。与表观遗传学和基因不同表达有关。

Histones --- Proteins associated with DNA in the chromosomes that are rich in basic amino acids (lysine or arginine) and virtually invariant throughout eukaryote evolution.

组蛋白：染色体中与DNA有关的蛋白质，富含赖氨酸和精氨酸，真核细胞进化中较为保守。

Holoenzyme --- The functional compound formed by the binding of an apoenzyme and its appropriate coenzyme.

全酶：酶蛋白和它相应的辅因子（辅酶或辅基）所构成的有功能的复合物。

Homeobox gene --- A gene that contains a conserved 180–base pair sequence termed a homeobox in its coding region, encoding a protein motif known as the homeodomain. The 60 amino acid residues of the homeodomain are a DNA-binding motif, which is consistent with the role of homeodomain proteins in transcriptional regulation of genes involved in development.

同源框基因        在编码区域有保守的长180bp的同源框序列，编码一种称为同源域的蛋白质基序。同源域的60个氨基酸为DNA结合基序，同源域蛋白与发育过程中基因的转录调控有关。

Homogeneously staining regions (HSRs) --- Chromosome regions that stain uniformly and represent amplified copies of a DNA segment.

均匀染色区（HSR）：染色体某一区域呈均匀无条纹的浅染区，为DNA片段重复扩增产物。

Homologous chromosomes (homologues) --- A pair of chromosomes, one inherited paternally, the other maternally, that pair with each other during meiosis I, undergo crossing over, and separate at anaphase I of meiosis. Homologous chromosomes are generally of similar size and shape when they are viewed under the microscope and contain the same loci, except for the two sex chromosomes in males (X and Y), which are only partially homologous. See pseudoautosomal region.

同源染色体：一条来自父本，一条来自母本，且形态、大小相同，在减数分裂前期相互配对的染色体。参见拟常染色体区域。

Homologous genes (homologues) --- Genes in a single species, or in different species, that have overall similar DNA sequences, that may have related biochemical functions, and that arose from a common ancestral gene. Orthologous and paralogous genes are types of homologous genes, but their meaning is more restricted.

同源基因：具有共同的进化起源，序列结构和功能相似的基因。

Homoplasmy --- The presence of only one type of mitochondrial DNA in the mitochondria of a single individual. Contrast with heteroplasmy.

纯质：某个体只有一种线粒体DNA的现象。相对当于杂质。

Homozygote (homozygous) --- An individual or genotype with identical alleles at a given locus on a pair of homologous chromosomes.

纯合子：在二倍体生物中，一对同源染色体上特定的基因座上有两个相同的等位基因的个体或细胞。

Host --- In molecular genetics, the organism in which a recombinant DNA molecule is isolated and grown; usually Escherichia coli or yeast.

宿主：允许重组DNA分子在其中复制的生物体。常用的宿主为埃利希大肠杆菌和酵母。

Housekeeping genes --- Genes expressed in most or all cells because their products provide basic functions.

持家基因：为维持细胞的基本生命活动所需而时刻都在表达的基因。

Housekeeping proteins --- Proteins expressed in virtually every cell that have fundamental roles in the maintenance of cell structure and function (versus specialty proteins).

持家蛋白：为维持细胞的基本生命活动所需而时刻都有表达的蛋白质（相当于特种蛋白）。

Human Genome Project --- A major research project, international in scope, that took place in the years 1990-2003 and resulted in the sequencing of a representative human genome and the genomes of many model organisms.

人类基因组计划：从1990-2003年进行的一项国际合作研究计划，主要对人类和一些模式生物的基因组进行测序。

Hybridization --- 1. In molecular biology, the bonding of two complementary single-stranded nucleic acid molecules according to the rules of base pairing. 2. In somatic cell genetics, fusion of two somatic cells, often from different organisms, to form a hybrid cell containing the genetic information of both parental cell types.

杂交：1.在分子生物学中，指两条互补的核苷酸单链分子形成稳定双链结构。2.在体细胞遗传学中，指源于不同生物的两个体细胞融合，形成含有双方遗传信息的杂交细胞。

Hydatidiform mole --- An abnormality of the placenta in which it grows to resemble a hydatid cyst or bunch of grapes, associated with very abnormal fetal development. In a complete mole, the karyotype is 46,XX, representing duplication of the chromosomes of the sperm with no maternal contribution. A partial mole is triploid, usually with an extra paternal chromosome set.

葡萄胎：一种类似葡萄状的胎盘，与异常胎儿发育有关。完全型葡萄胎的核型为46,XX，为精子染色体重复所致。部分型葡萄胎为三倍体，多余的一套父方染色体。

Identity by descent --- Two individuals in a family who have the same allele or alleles at a locus because they inherited the alleles from a common ancestor. See coefficient of inbreeding.

相同血统：两个个体有共同的祖先，故同一基因座上携带相同的等位基因。参见近交系数。