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59 Cards in this Set
- Front
- Back
Genetics |
The field of study concerned with the inheritance of traits. |
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Heredity |
The transmission of traits from parents to offspring via genetic information. |
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Trait |
Any heritable characteristic of an individual. |
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Model Organism |
An organism selected for intensive scientific study based on features that make it easy to work with in the hope that findings will apply to other species. |
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Pollen Grain |
In seed plants, a male gametophyte enclosed within a protective coat. |
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Cross-fertilization |
A mating that combines gametes from different individuals, as opposed to combining gametes from the same individual. |
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Phenotype |
The detectable physical and physiological traits that determine an individual's genetic make up. Also the specific trait associated with a particular allele. |
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Pure Line |
In animal or plant breeding, a strain of individuals that produce offspring identical to themselves when self-pollinated or crossed to another member of the same population. Pure lines are homozygous for most, if not all, genetic loci. |
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Hybrid |
The offspring of parents from two different strains, populations, or species. |
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Parental Generation |
The adult organisms used in the first experimental cross in a formal breeding experiment. |
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F1 Generation |
First filial generation. The first generation of offspring produced from a mating, the offspring of the parental generation. |
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Monohybrid Cross |
A mating between two parents that are both heterozygous for a given gene. |
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Recessive |
Referring to an allele whose phenotypic effect is observed only in homozygous individuals. |
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Dominant |
Referring to an allele that determines the phenotype of a heterozygous individual. |
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Huntington's Disease |
A degenerative brain disease of humans caused by an autosomal dominant allele. |
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Reciprocal Cross |
A breeding experiment in which the mother's and father's phenotypes are the reverse of that examined in a previous breeding experiment. |
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Particulate Inheritence |
The observation that genes from two parents do not blend together to form a new physical entity in offspring, but instead remain separate or particle-like. |
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Genotype |
All of the alleles of every gene present in a given individual. May refer specifically to the alleles of a particular set of genes under study. |
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Principle of Segregation |
The concept that each pair of hereditary elements (alleles of the same gene) separate from each other during the formation of offspring. One of Mendel's two principles of genetics. |
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Homozygous |
Having two identical alleles of a certain gene. |
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Heterozygous |
Having two different alleles of a certain gene. |
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Punnett Square |
A diagram that depicts the genotypes and phenotypes that should appear in offspring of a certain cross. Invented by R.C. Punnett. |
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Genetic Model |
A set of hypotheses that explain how a certain trait is inherited. |
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Dihybrid Cross |
A mating between two parents that are heterozygous for both of the two genes being studied. |
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Principle of Independent Assortment |
The concept that each pair of hereditary elements (alleles of the same gene) behaves independently of other genes during meiosis. One of Mendel's two principles of genetics. |
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Phenotypic Ratios of a Dihybrid Cross |
9:3:3:1 |
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Testcross |
The breeding of an individual of an unknown genotype with an individual having only recessive alleles for the traits of interest in order to infer the unknown genotype from the phenotypic ratios seen in offspring. |
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Phenotypic Ratios of a Testcross |
1:1:1:1 |
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Gene |
A section of DNA that encodes information for building one or more related polypeptides or functional RNA molecules along with the regulatory sequences required for its transcription. |
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Allele |
A particular version of a gene. |
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Locus |
A gene's physical location on a chromosome. |
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Chromosome Theory of Inheritance |
The principle that genes are located on chromosomes and that patterns of inheritance are determined by the behaviour of chromosomes during meiosis. |
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Wild Type |
The most common phenotype seen in a population; especially the most common phenotype in wild populations compared with inbred strains of the same species. |
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Mutation |
Any change in the hereditary material of an organism. |
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Mutant |
A carrier of a mutation. |
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X-linked Inheritance |
Inheritance patterns for genes located on the mammalian X chromosome. Also called X-linkage. |
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Y-linked Inheritance |
Inheritance patterns for genes located on the mammalian Y chromosome. Also called Y-linkage. |
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Sex-linked Inheritance |
Inheritance patterns observed in genes carried on sex chromosomes, so females and males have different numbers of alleles of a gene and may pass its trait only to one sex of offspring. Also called sex-linkage. |
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Autosomal Inheritance |
The inheritance patterns that occur when genes are located on autosomes rather than on sex chromosomes. |
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Thomas Hunt Morgan |
Fruit fly eye colour experiment. Showed that genes are located on chromosomes. Also showed that linked genes are inherited together unless crossing over occurs. |
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Linkage |
A physical association between two genes because they are on the same chromosome; the inheritance patterns resulting from this association. An exception from independent assortment. |
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Recombinant |
Possessing a new combination of alleles. May refer to a single chromosome or DNA molecule or to an entire organism. Happens when crossing over occurs. |
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Genetic Map |
An ordered list of genes on a chromosome that indicates their relative distances from each other. Also called a linkage map or a meiotic map. |
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Incomplete Dominance |
An inheritance pattern in which the heterozygote phenotype is a blend or combination of both homozygote phenotypes. |
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How to use centiMorgan (cM) |
Genes that are 50cM apart cross over 50% of the time. |
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Codominance |
An inheritance pattern in which heterozygotes exhibit both of the traits seen in either kind of homozygous individual. |
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Multiple Allelism |
In a population, the existence of more than two alleles of the same gene. |
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Polymorphism |
The occurrence of more than two distinct phenotypes of a trait in a population due to multiple allelism. |
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Pleiotropy |
The ability of a single gene to affect more than one phenotypic trait. |
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Marfan Syndrome |
A human syndrome involving increased height, long limbs and fingers, an abnormally shaped chest, and heart disorders. Probably caused by mutation in one pleiotropic gene. |
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Phenylketonuria (PKU) |
A disease caused by the inability to process the amino acid phenylalanine. |
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Discrete Trait |
An inherited trait that exhibits distinct phenotypic forms rather than the continuous variation characteristic of a quantitative trait such as body height. |
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Quantitative Trait |
A heritable feature that exhibits phenotypic variation along a smooth, continuous scale of measurement (like height), rather than the distinct forms characteristic of discrete traits. Have a normal distribution on a graph. |
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Polygenic Inheritance |
The inheritance patterns that result when many genes influence one trait. |
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Gene-by-gene Interaction |
In discrete traits, the phenotype associated with an allele depends on which alleles are present at another gene. |
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Gene-by-environment Interaction |
Phenotype influenced by environment experienced by individual (i.e. plant height and sun exposure). |
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Pedigree |
A family tree of parents and offspring, showing inheritance of particular traits of interest. |
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Carrier |
A heterozygous individual carrying a normal allele and a recessive allele for an inherited trait; does not display the phenotype of the trait but can pass the recessive gene to the offspring. |
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Hemophilia |
A human disease, caused by an X-linked recessive allele, that is characterized by defects in the blood-clotting system. |