Testcrossing | definition of testcrossing by Medical dictionary
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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.
testcross (tĕst′krôs′, -krŏs′)
A cross between an individual exhibiting the dominant phenotype of a trait and an individual that is homozygous recessive for that trait in order to determine the genotype of the dominant individual.
To subject to a testcross.
Etymology: L, testum + crux, cross
1 a cross between a dominant and a recessive phenotype to determine either the degree of genetic linkage or whether the dominant phenotype is a result of a homozygous or a heterozygous genotype.
a subject undergoing such a test. See also backcross
Fig. 295 Testcross. A testcross to find the genotype of the unknown parent.
testcross a cross in which one partner is homozygous (see HOMOZYGOTE for the recessive alleles of the genes being investigated. The testcross progeny will indicate the GENOTYPE of the unknown parent. See Fig. 295 . Test crosses are used extensively in experiments to establish GENETIC LINKAGE. See also BACKCROSS.
References in periodicals archive
Adequate seed was not available for testcrossing
after producing the backcross generation of (B37 x B84).
Finally, epistatic interactions among resistance loci will negate the possibility of phenotypically selecting plants with multiple resistance factors without tedious testcrossing
to BS11C0 removes the effects of genetic drift by restoring heterozygosity to those loci that may have become fixed in the population by drift.
2a) was evaluated by testcrossing