Identify the test cross from the following options:
Identify the test cross from the following options:
The correct option is C Rr x rr
Test cross is conducted to know the genotype of the organism showing dominant phenotype as it can be homozygous or heterozygous.
In order to determine the genotype, the organism with dominant phenotype for a particular character is crossed with the recessive individual for the same character.
If all the offspring obtained from the cross exhibit a dominant phenotype, then the unknown genotype is homozygous dominant.
If both the dominant and recessive phenotypes are obtained in the ratio of 1 : 1, then the unknown genotype is heterozygous dominant.
Hence, in the options given, option c represents test cross as one of the parents is heterozygous dominant (Rr) and the other is recessive (rr).
Option a represents a cross between two homozygous dominant individuals (RR x RR).
Option b represents a cross between two heterozygous dominant individuals (Rr x Rr).
Option d represents a cross between two recessive individuals (rr x rr).
The crosses given in the options a, b and d cannot be considered as a test cross.
Test cross is conducted to know the genotype of the organism showing dominant phenotype as it can be homozygous or heterozygous.
In order to determine the genotype, the organism with dominant phenotype for a particular character is crossed with the recessive individual for the same character.
If all the offspring obtained from the cross exhibit a dominant phenotype, then the unknown genotype is homozygous dominant.
If both the dominant and recessive phenotypes are obtained in the ratio of 1 : 1, then the unknown genotype is heterozygous dominant.
Hence, in the options given, option c represents test cross as one of the parents is heterozygous dominant (Rr) and the other is recessive (rr).
Option a represents a cross between two homozygous dominant individuals (RR x RR).
Option b represents a cross between two heterozygous dominant individuals (Rr x Rr).
Option d represents a cross between two recessive individuals (rr x rr).
The crosses given in the options a, b and d cannot be considered as a test cross.
