Question

What is a test cross? What is the importance of a test cross? And what are the results

of a test cross for a single trait?

Answer 1

Test cross helps in the identification of the genotype of the unknown parent by crossing it with a recessive parent. Analysis of the offsprings proportion of recessive and dominant phenotypes determines the heterozygosity and homozygosity of the parent. If all offsprings obtained by a test cross are dominant, parent is homozygous. If offsprings obatined are half dominant and half recessive then the parent is heterozygous. Test cross ratio for a singke trait is 1:1.