AskDefine | Define testcross

Dictionary Definition

test-cross n : 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: testcross]testcross n : 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]

Extensive Definition

In genetics, a test cross, first introduced by Mendel, is used to determine if an individual exhibiting a dominant trait is homozygous or heterozygous for that trait.
Test crosses involve breeding the individual in question with another individual that expresses a recessive version of the same trait. If all offspring display the dominant phenotype, the individual in question is homozygous dominant; if the offspring display both dominant and recessive phenotypes, then the individual is heterozygous.
In some sources, the "test cross" is defined as being a type of back cross between the recessive homozygote and F1 generation.
testcross in French: Croisement de contrôle
testcross in Italian: Reincrocio
testcross in Polish: Krzyżówka testowa
testcross in Turkish: Geri çaprazlama
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