testcross


testcross
/test"kraws', -kros'/, n.
a genetic test for heterozygosity in which an organism of dominant phenotype, but unknown genotype, is crossed to an organism recessive for all markers in question.
[1930-35; TEST1 + CROSS]

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Experiment in which an organism with unknown genetic makeup is mated with an organism whose entire genetic makeup for a trait is known, to determine which genes are carried by the former.

In a breed of dog, for example, in which the gene for black coat colour is dominant over the gene for red coat colour (see dominance), a dog with a black coat may be pure (with two genes for black coat colour) or hybrid (with one gene for black and one for red). When its mating with a red-coated dog (which always has two genes for red coat colour only) produces only black offspring, the black-coated parent must be pure, whereas if some of the young are red, the parent must be hybrid.

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      the mating of an organism whose genetic constitution is unknown with an organism whose entire genetic makeup for a trait is known, to determine which genes are carried by the former. In a breed of dog, for example, in which the gene for black coat colour is dominant over (suppresses the effect of) the gene for red coat colour, a dog with a black-coloured coat may be either pure breeding, with two genes for black coat colour, or hybrid, with one gene for black coat colour and one for red coat colour. To determine which genetic endowment the dog has, it is mated to a red-coated dog, which invariably has two genes for red coat colour only. If all the offspring are black, the black-coated parent must be pure breeding and have both genes for black coat colour; if some of the young are red, the parent must be hybrid and have one gene for black coat colour and one for red coat colour.

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Universalium. 2010.

Look at other dictionaries:

  • testcross — noun Date: 1934 a genetic cross between a homozygous recessive individual and a corresponding suspected heterozygote to determine the genotype of the latter • testcross transitive verb …   New Collegiate Dictionary

  • testcross — Crossing of an unknown genotype to a recessive homozygote so that the phenotype of the progeny corresponds directly to the chromosomes carried by the parents of unknown genotype. SYN: backcross (2). * * * test·cross tes(t) .krȯs n a genetic… …   Medical dictionary

  • testcross — noun a cross between an organism whose genotype for a certain trait is unknown and an organism that is homozygous recessive for that trait so the unknown genotype can be determined from that of the offspring • Syn: ↑test cross • Hypernyms:… …   Useful english dictionary

  • testcross — TEST CROSS s. n. (biol.) încrucişare între un individ cu caracter dominant, necunoscut genetic, cu un test complet recesiv, pentru a determina dacă individul respectiv este homozigot sau heterozigot. (< engl. test cross) Trimis de raduborza,… …   Dicționar Român

  • testcross — test•cross [[t]ˈtɛstˌkrɔs, ˌkrɒs[/t]] n. gen a genetic test for heterozygosity in which an organism of dominant phenotype, but unknown genotype, is crossed with an organism recessive for all markers in question • Etymology: 1930–35 test′ cross ,… …   From formal English to slang

  • testcross — A cross between a genetically unknown individual and a recessive tester to determine whether the individual in question is heterozygous or homozygous for a certain allele. It can also used as a method to test for linkage, i.e. to estimate… …   Glossary of Biotechnology

  • Monohybrid cross — is a method of determining the inheritance pattern of a trait between two single organisms. [1] A monohybrid cross is a cross between parents who are heterozygous at one locus; for example, Bb x Bb (see the Punnett). Example: B = brown. b = blue …   Wikipedia

  • Diallel — A Diallel is a mating scheme used by plant breeders and geneticists to test for general and specific combining ability as well as genetic effects behind quantitative traits.Hallauer, A. R. and J. B. Miranda Filho. 1988 Quantitative genetics in… …   Wikipedia

  • heredity — /heuh red i tee/, n., pl. heredities. Biol. 1. the transmission of genetic characters from parents to offspring: it is dependent upon the segregation and recombination of genes during meiosis and fertilization and results in the genesis of a new… …   Universalium

  • backcross — 1. Mating of an individual heterozygous at one or more loci to an individual homozygous at the same loci. 2. SYN: testcross. * * * back·cross bak .krȯs vt to cross (a first generation hybrid) with one of the parental types backcross n a mating… …   Medical dictionary


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