27 an introduction to genetic analysis文档格式.docx

1、adaptive landscape The surface plotted in a three-dimensional graph, with all possible combinations of allele frequencies for different loci plotted in the plane and with mean fitness for each combination plotted in the third dimension.adaptive peak A high point （perhaps one of several） on an adapti

2、ve landscape; selection tends to drive the genotype composition of the population toward a combination corresponding to an adaptive peak.adaptive surface See adaptive landscape.adaptor protein A protein that binds to certain specific phosphorylated amino acid sequences on a second protein, often a t

3、ransmembrane receptor, and associates with still other proteins, thereby allowing a complex of proteins to “dock” to the receptor. This docking brings proteins of this complex in proximity to one another and, by doing so, permits propagation of an intracellular signal in a signal transduction pathwa

4、y.additive genetic variance Genetic variance associated with the average effects of substituting one allele for another.adenine A purine base that pairs with thymine in the DNA double helix.adenosine The nucleoside containing adenine as its base.adenosine triphosphate See ATP.adjacent segregation In

5、 a reciprocal translocation, the passage of a translocated and a normal chromosome to each of the poles.ADP Adenosine diphosphate.Ala Alanine （an amino acid）.albino A pigmentless “white” phenotype, determined by a mutation in a gene coding for a pigment-synthesizing enzyme.alkylating agent A chemica

6、l agent that can add alkyl groups （for example, ethyl or methyl groups） to another molecule; many mutagens act through alkylation.allele One of the different forms of a gene that can exist at a single locus.allele frequency A measure of the commonness of an allele in a population; the proportion of

7、all alleles of that gene in the population that are of this specific type.allopatric speciation The process of the splitting of a species into two or more new species that occurs between populations that are geographically isolated from each other.allopolyploid See amphidiploid.allosteric transition

8、 A change from one conformation of a protein into another.alternate segregation In a reciprocal translocation, the passage of both normal chromosomes to one pole and both translocated chromosomes to the other pole.alternation of generations The alternation of gametophyte and sporophyte stages in the

9、 life cycle of a plant.alternative splicing The process by which different mRNAs are produced from the same primary transcript, through variations in the splicing pattern of the transcript. Multiple mRNA “isoforms” can be produced in a single cell or the different isoforms can display different tiss

10、ue-specific patterns of expression. If the alternative exons fall within the open reading frames of the mRNA isoforms, different proteins will be produced by the alternative mRNAs.amber codon The codon UAG, a nonsense codon.amber suppressor A mutant allele coding for a tRNA whose anticodon is altere

11、d in such a way that the tRNA inserts an amino acid at an amber codon in translation.Ames test A widely used test to detect possible chemical carcinogens; based on mutagenicity in the bacterium Salmonella.amino acid A peptide; the basic building block of proteins （or polypeptides）.amniocentesis A te

12、chnique for testing the genotype of an embryo or fetus in utero with minimal risk to the mother or the child.AMP Adenosine monophosphate.amphidiploid An allopolyploid; a polyploid formed from the union of two separate chromosome sets and their subsequent doubling.amplification The production of many

13、 DNA copies from one master region of DNA.anaphase An intermediate stage of nuclear division during which chromosomes are pulled to the poles of the cell.aneuploid cell A cell having a chromosome number that differs from the normal chromosome number for the species by a small number of chromosomes.a

14、nimal breeding The practical application of genetic analysis for development of lines of domestic animals suited to human purposes.annealing Spontaneous alignment of two single DNA strands to form a double helix.antibody A protein （immunoglobulin） molecule, produced by the immune system, that recogn

15、izes a particular substance （antigen） and binds to it.anticodon A nucleotide triplet in a tRNA molecule that aligns with a particular codon in mRNA under the influence of the ribosome so that the amino acid carried by the tRNA is inserted in a growing protein chain.antigen A molecule that is recogni

16、zed by antibody （immunoglobulin） molecules. Generally, multiple antibody molecules can recognize a given antigen.antiparallel A term used to describe the opposite orientations of the two strands of a DNA double helix; the 5 end of one strand aligns with the 3 end of the other strand.AP site Apurinic

17、 or apyrimidinic site resulting from the loss of a purine or pyrimidine residue from the DNA.Arg Arginine （an amino acid）.ascospore A sexual spore from certain fungus species in which spores are found in a sac called an ascus.ascus In fungi, a sac that encloses a tetrad or an octad of ascospores.ase

18、xual spore See spore.Asn Asparagine （an amino acid）.Asp Aspartate （an amino acid）.ATP （adenosine triphosphate） The “energy molecule” of cells, synthesized mainly in mitochondria and chloroplasts; energy from the breakdown of ATP drives many important cell reactions.attached X A pair of Drosophila X

19、chromosomes joined at one end and inherited as a single unit.attenuator A region adjacent to the structural genes of the trp operon; this region acts in the presence of tryptophan to reduce the rate of transcription from the structural genes.autonomous controlling element A controlling element that

20、seems to have both regulator and receptor functions combined in a single unit that enters a gene and causes an unstable mutation.autonomous phenotype A genetic trait in multicellular organisms in which only genotypically mutant cells exhibit the mutant phenotype. Conversely, a nonautonomous trait is

21、 one in which genotypically mutant cells cause other cells （regardless of their genotype） to exhibit a mutant phenotype.autonomous replication sequence （ARS） A segment of a DNA molecule needed for the initiation of its replication; generally a site recognized and bound by the proteins of the replica

22、tion system.autophosphorylation The process by which a protein kinase phosphorylates specific amino acid residues on itself.autopolyploid A polyploid formed from the doubling of a single genome.autoradiogram A pattern of dark spots in a developed photographic film or emulsion, in the technique of au

23、toradiography.autoradiography A process in which radioactive materials are incorporated into cell structures, which are then placed next to a film or photographic emulsion, thus forming a pattern on the film corresponding to the location of the radioactive compounds within the cell.autoregulatory lo

24、op The process by which the expression of a gene is controlled by its own gene product.autosome Any chromosome that is not a sex chromosome.auxotroph A strain of microorganisms that will proliferate only when the medium is supplemented with some specific substance not required by wild-type organisms

25、.BBAC Bacterial artificial chromosome; an F plasmid engineered to act as a cloning vector that can carry large inserts.back mutation See reversion.bacteriophage （phage） A virus that infects bacteria.balanced polymorphism Stable genetic polymorphism maintained by natural selection.balancer A chromoso

26、me with multiple inversions, used to retain favorable allele combinations in the uninverted homolog.Balbiani ring A large chromosome puff.Barr body A densely staining mass that represents an inactivated X chromosome.base analog A chemical whose molecular structure mimics that of a DNA base; because

27、of the mimicry, the analog may act as a mutagen.bead theory The disproved hypothesis that genes are arranged on the chromosome like beads on a necklace, indivisible into smaller units of mutation and recombination.bimodal distribution A statistical distribution having two modes.binary fission The pr

28、ocess in which a parent cell splits into two daughter cells of approximately equal size.biparental zygote A Chlamydomonas zygote that contains cpDNA from both parents; such cells are generally rare.blast cell A cell that divides, generally asymmetrically, to give rise to two different progeny cells.

29、 One is a blast cell just like the parental cell and the other is a cell that enters a differentiation pathway. In this manner, a continuously propagating cell population can maintain itself and spin off differentiating cells.blastoderm In an insect embryo, the layer of cells that completely surrounds an internal mass of yolk.blastula An early developmental stage of lower vertebrate embryos, in which the embryo consists of a single layer of cells surrounding the central yolk.blending inheritance A disc