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Definition
| A complete set of genetic instructions for any organisms, encoded in nucleic acids (DNA or RNA). |
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| Encompasses the basic principles of heredity and how traits are passed from one generation to the next. Relation btwn chromosomes and heredity. |
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| Concerns the chemical nature of gene itself: how genetic information is encoded, replicated, and expressed. |
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| Explores the genetic composition of groups of individual members of the same species (populations) and how that composition changes over time and geographic space. Study of evolution. |
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| Organisms having characteristic that make them particularly useful for genetic analysis and about which a tremendous amount of genetic information has accumulated. |
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| Specific particles, later called gemmules, carry information from various parts of the body to the reproductive organs, from which they are passed to the embryo at the moment of conception. (Incorrect) |
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| Inheritance of Acquired Characteristics |
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Definition
| Acquired traits become incorporated into one's hereditary information and are passed on to offspring. |
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| Inside the egg or sperm there exists a tiny miniature adult, a homunculus, which simply enlarges during development. All traits would be inherited from only one parent. |
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| Offspring are a blend, or mixture, of parental traits. Today, traits do not blend. |
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| All life is composed of cells, cells arise only from preexisting cells, and the cell is the fundamental unit of structure and function in living organisms. |
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| Cells in the reproductive organs carry a complete set of genetic information that si passed to the egg and sperm. (False) |
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| Complex of DNA and histone proteins |
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| usually alike in structure and size, and each carries genetic information for the same set of hereditary characteristics. |
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| Two sets of genetic information |
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| Cells with a single set of chromosomes. |
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| Natural ends, the tips, of a linear chromosome, they serve to stabilize the chromosome ends. |
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| Life story of a cell, the stages through which it passes from one division to the next. |
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| Period btwn cell divisions, in which the cell grows, develops, and prepares for cell division. |
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| The period of active cell division. Contains mitosis, process of nuclear division and cytokinesis, cytoplasmic division. |
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Definition
| Stage of mitosis. Chromosomes contract and become visible, the cytoskeleton breaks down, and the mitotic spindle begins to form |
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Definition
| Stage of mitosis. The nuclear membrane braks down and the spindle microtubules attach to the chromosomes |
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| Stage of mitosis. Chromosomes align in the center of the cell. |
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| Stage of mitosis in which chromatids separate and move toward the spindle poles. |
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| Stage of mitosis. The chromosomes arrive at the spindle poles, the nuclear membrane re-forms, and the chromosomes relax and lengthen. |
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| Process in which chromosomes of a eukaryotic cell divide to give rise to haploid reproductive cells. |
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| Fusion of gametes, or sex cells, to form a zygote. |
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| A very close pairing association |
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| Homologous chromosomes exchange genetic information |
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| Each homologous pair of synapsed chromosomes consists of four chromatids. |
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| Period btwn meiosis I and meiosis II. |
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Definition
| Creating new combinations of alleles on a chromatid. |
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Definition
| A protein that holds the chromatids together, is key to the behavior of chromosomes in mitosis and meiosis. |
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Definition
| A genetic factor (region of DNA) that helps determine a characteristic |
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Definition
| One of two or more alternate forms of a gene |
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Definition
| Specific place on a chromosome occupied by an allele |
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Definition
| Set of alleles possessed by an individual organism. |
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| An individual organism possessing two different alleles at a locus |
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Definition
| An individual organism possessing two of the same alleles at a locus. |
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| Character or Characteristic |
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Definition
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Definition
| The appearance or manifestation of a character. |
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| Those between parents that differed in a single characteristic. |
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| The first generation, the parents of the cross. |
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Definition
| The offspring from the parents in the P generation, the children. |
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Definition
| Crosses in which the phenotypes of the male and female parents are reversed. For example: in one cross, a tall male is crossed with a short female and, in the other cross, a short male is crossed with a tall female. |
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Definition
| Offspring of the F2 generation, the grandkids. |
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Definition
| Refers to an allele or a phenotype that is expressed in homozygotes (AA) and in heterozygotes (Aa); only the dominant allele is expressed in a heterozygote phenotype. |
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Definition
| Refers to an allele or phenotype that is expressed only when homozygous. The recessive allele is not expressed in the heterozygote phenotype. |
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| Principle of segregation (Mendel's first law) |
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Definition
| Individual diploid organism possesses two alleles for any particular characteristic. These alleles segregate into gametes in equal proportion. |
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Definition
| When two different alleles are present in a genotype, only the trait encoded by one of them--the 'dominate' allele--is observed in the phenotype. |
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| Chromosome theory of heredity |
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Definition
| The theory that genes are located on chromosomes. |
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Definition
| Type of cross between an F1 genotype and eiter of the parental genotypes. |
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Definition
| Constructed by drawing a grid, putting the gametes produced by one parent along the upper edge and the gametes produced by the other parent on the left side. |
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Definition
| Expresses the likelihood of the occurrence of a particular event. |
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Definition
| The probability of two or more independent events occurring together is calculated by multiplying their independent probabilities. |
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Definition
| The probability of any one of two or more mutually exclusive events is calculated by adding the probabilities of these events. |
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Definition
| One individual of unknown genotype is crossed with another individual with a homozygous recessive genotype for the trait in question. |
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Definition
| Heterozygote has a phenotype intermediate between the phenotypes of two homozygotes. |
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Definition
| A cross that differed in two characteristics. |
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Term
| Principle of Independent Assortment (Mendel's second law) |
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Definition
| Important principle of heredity discovered by Mendel that states that each diploid individual possesses two alleles at a locus and that these two alleles separate when gametes are formed, one allele going into each gamete. |
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Term
| Goodness-of-fit Chi-Square test |
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Definition
| Statistical test used to evaluate how well a set of observed values fit the expected values. The probability associated with a calculated chi-square value is the probability that the differences between the observed and the expected values may be due to chance. |
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Definition
| Both sexs are present in the same organism |
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Definition
| An organism bears both male and female reproductive structures. |
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Definition
| An organism has either male or female reproductive structures. |
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Definition
| Sex is determined by a pair of chormosomes which differ between males and females. |
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Definition
| The nonsex chromosomes, which are the same for males and females. |
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Definition
| Similarities in the telomere the tips that allows the X and Y chromosome to pair, event hough they are not generally homologous. |
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Term
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Definition
| Sex determination in which the sexual phenotype is specified by genes at one or more loci, but there are no obvious differences in the chromosomes of males and females. |
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| Sequential Hermaphroditism |
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Definition
| Phenomenon in which the sex of an individual organism changes in the course of it's lifetime |
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Term
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Definition
| Sex-determining system in which sexual phenotype is controlled by a balance between genes on the X chromosome and genes on the autosomes. |
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Term
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Definition
| Ratio of the number of X chromosomes to the number of haploid autosomal sets of chromosomes; determines sex in fruit flies. |
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Term
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Definition
| Human condition in which cells contain a single X chromosome and no Y chromosome (XO). Persons with Turner syndrome are female in appearance but do not undergo puberty and have poorly developed female secondary sex characteristics; most are sterile but have normal intelligence. |
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Term
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Definition
| Human condition in which cells contain one or more Y chromosomes along with multiple X chromosomes (most commonly XXY but may also be XXXY, XXXXXY, or XXYY). Persons with Klinefelter syndrome are male in appearance but frequently possess small testes, some breast enlargement, and reduced facial and pubic hair; often taller than normal and sterile, most have normal intelligence. |
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Term
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Definition
| Human condition in which cells contain three X chromosomes. A perosn with triplo-X syndrome has a female phenotype without distinctive features other than a tendency to be tall and thin; a few such women are sterile, but many menstruate regularly and are fertile. |
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Term
| Sex-determining region Y (SRY) Gene |
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Definition
| On the Y chromosome, a gene that triggers male development; also known as the testis-determining factor (TDF) gene |
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Term
| Sex-linked Characteristic |
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Definition
| Characteristic determined by a gene or genes on sex chromosomes. |
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Term
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Definition
| Characteristic determined by a gene or genes on the X Chromosome |
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Term
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Definition
| Characteristic determined by a gene or genes on the Y chromosomes. |
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Definition
| Posession of a single allele at a locus. Males of organisms with XX-XY sex determination are hemizygous for X-linked loci, because their cells possess a single X charmosome. |
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Definition
| Failure of homologous chromosomes or sister chromatids to separate in meiosis or mitosis. |
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Definition
| Equalization in males and females of amount of protein produced by X-linked genes. In placental mammals, dosage compensation is accomplished by the random inzctivation of one X chromosome in the cells of females. |
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Term
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Definition
| Condensed, darkly staining structure that is found in most cells of female placental mammals and is an inactivated X chromosome. |
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Definition
| One X chromosome in each female cell becomes inactivated (barr body) and suggests that which X becomes inactivated is random and varies from cell to cell. |
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Definition
| Type of allelic interaction in which the heterozygote simultaneously expresses traits of both homozygotes |
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Definition
| Refers to the genotype that does not always express the expected phenotype. Some individuals possess the genotype for a trait but do not express the phenotype. |
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Definition
| Percentage of individuals with a particular genotype that express the phenotype expected of that genotype. |
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Definition
| Degree to which a trait is expressed |
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Definition
| Causes the death of an individual organsim, often early in development, and so the organism does not appear in the progeny of a genetic cross. Recessive lethal alleles kill individuual organisms that are homozygous for the allele; dominant lethals kill both heterozygotes and homozygotes. |
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Definition
| Presence in a group of individuals of more than two alleles at a locus. Although, for the group, the locus has more than two alleles, each member of the group has only two of the possible alleles. |
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Definition
| Interactions between genes at different loci that affect the same characteristic. |
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Definition
| Type of gene interaction in which a gene at one locus masks or supresses the effects of a gene at a different locus. |
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Definition
| Masks or supresses the effect of a gene at a different locus. |
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Definition
| Gene that is masked or suppressed by the action of a gene at a different locus. |
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Definition
| Test designed to determine whether two different mutations are at the same locus (are allelic) or at different loci (are nonallelic). Two individuals that are homozygous for two indeendently derived mutations are crossed, producing F1 progeny that are heterozygous for the mutations. If the mutations are tat the same locus, the F1 will have a mutant phenotype. If the mutations are at different loci, the F1 will have a wild-type phenotype. |
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Term
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Definition
| Two different mutations in the heterozygous condition are exhibited as the wild-type phenotype; indicates that the mutations are at different loci. |
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| Sex-influenced Characteristic |
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Definition
| Encoded by autosomal genes that are more readily expressed in one sex. For example, an autosomal dominant gene may have higher penetrance in males than in females or an autosomal gene may be dominant in males but recessive in females. |
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| Sex-limited characteristic |
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Definition
| Encoded by autosomal genes and expressed in onlky one sex. Both males and females carry genes for sex-limited characteristics, but the characteristics appear in only one of the sexes. |
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Definition
| Inheritance of characteristics encoded by genes located in the cytoplasm. Because the cytoplasm is usually contributed entirely by only one parent, most cytoplasmically inherited characteristics are inherited from a single parent. |
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Definition
| Determines the phenotype of an offspring. Inherits genes for the characteristics from both parents, but the offspring's phenotype is determined not by its own genotype but by the nuclear genotype of its mother. |
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Definition
| Differential expression of a gene that depends on te sex of the parent that transmitted the gene. If the gene is inherited from the father, its expression is different from that if it is inherited from the mother |
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Term
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Definition
| Phenonmena due to alterations to DNA that do not include changes in the base sequence; often affect the way in which the DNA sequences are expressed. Such alterations are often stable and heritable in the sense that they are passed from one cell to another. |
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Definition
| Increasing severity or ealier age of onset of a genetic trait in succeeding generations. For example, symptoms of a genetic disease may become more severe as the trait is passed from generation to generation. |
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Definition
| Range of phenotypes produced by a particular genotype in different enviornmental conditions. |
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| Temperature-Sensitive Allele |
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Definition
| Expressed only at certain temperatures. |
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Definition
| Phenotype that is produced by environmental effects and is the same as the phenotype produced by a genotype. |
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| Discontinuous Characteristic |
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Definition
| Exhibits only a few, easily distinguished phenotypes. An example is seed shape in which seeds are either round or wrinkled. |
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| Continuous Characteristic |
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Definition
| Displays a large number of possible phenotypes that are not easily distinguished, such as human height. |
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| Quantitative Characteristic |
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Definition
| Continuous characteristic; displays a large number of possible phenotypes, which must be described by a quantitative measurement. |
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Definition
| Encoded by genes at many loci |
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Definition
| A single genotype influences multiple phenotypes. |
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| Multifactorial Characteristic |
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Definition
| Determined by multiple genes and environmental factors. |
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Definition
| Pictorial representation of a family history outlining the inheritance of one or more traits or diseases. |
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Definition
| A person with a trait of disease for whom a pedigree is constructed. |
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Definition
| Mating between related individuals. |
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Definition
| Nonidentical twins that arise when two different eggs are fertilized by two different sperm; also called fraternal twins |
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Definition
| Identical twins that arise when a single egg fertilized by a single sperm splits into two separate embryos. |
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Definition
| Percentage of twin pairs in which both twins have a particular trait. |
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