Question

A cross used to ascertain whether a dominant is homozygous or heterozygous is

• A. Reciprocal
• B. Back cross
• C. Test cross
• D. Monohybrid

Answer 1

The correct option is C Test cross

In genetics, a test cross, first introduced by Gregor Mendel, involves the breeding of a phenotypically dominant individual with a phenotypically recessive individual, in order to determine the zygosity of the former by analyzing proportions of offspring phenotypes. Zygosity can either be heterozygous or homozygous. Those that are heterozygous have one dominant and one recessive allele. Individuals that are homozygous dominant have two dominant alleles, and those that are homozygous recessive have two recessive alleles.
The genotype that an offspring has for each of its genes is determined by the alleles inherited from its parents. The combination of alleles is a result of the maternal and paternal chromosomes contributed from each gamete at fertilization of that offspring. During meiosis in gametes, homologous chromosomes experience genetic recombination and segregate randomly into haploid daughter cells, each with a unique combination of maternally and paternally coded genes. Dominant alleles will override the expression of recessive alleles.