Question
What is a test-cross?
Answer
A test cross, also known as a backcross, is a genetic cross used to determine the genotype of an individual displaying a dominant trait. A test cross is made between a homozygous recessive individual/parent and a parent/individual of unknown genotype (to determine whether the unknown genotype is homozygous or heterozygous for dominant gene)
In a test cross, if the individual with the dominant trait is homozygous dominant, all the offspring will show the dominant phenotype. On the other hand, if the individual is heterozygous, half of the offspring will exhibit the dominant phenotype, and the other half will show the recessive phenotype. This outcome occurs because the homozygous recessive parent contributes only the recessive allele to the offspring, while the other parent may contribute either the dominant or recessive allele.
The test cross (back cross) is a valuable tool in genetics for determining the genotype of individuals with dominant traits, especially when dealing with organisms with unknown genetic backgrounds. By conducting a test cross and analyzing the phenotypes of the offspring, geneticists and breeders can gain insights into the genetic makeup of the individual being tested.
Read on Genetics including Test Cross, Continuous and Discontinuous Variation, Structure and Properties of Chromosomes, and the Structure of DNA
In a test cross, if the individual with the dominant trait is homozygous dominant, all the offspring will show the dominant phenotype. On the other hand, if the individual is heterozygous, half of the offspring will exhibit the dominant phenotype, and the other half will show the recessive phenotype. This outcome occurs because the homozygous recessive parent contributes only the recessive allele to the offspring, while the other parent may contribute either the dominant or recessive allele.
The test cross (back cross) is a valuable tool in genetics for determining the genotype of individuals with dominant traits, especially when dealing with organisms with unknown genetic backgrounds. By conducting a test cross and analyzing the phenotypes of the offspring, geneticists and breeders can gain insights into the genetic makeup of the individual being tested.
Read on Genetics including Test Cross, Continuous and Discontinuous Variation, Structure and Properties of Chromosomes, and the Structure of DNA
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