testcross(redirected from testcrossing)
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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.
Synonym(s): backcross (2)
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.
tr.v. test·crossed, test·crossing, test·crosses
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.
2 a subject undergoing such a test. See also backcross.