Question

2. A particular genetic cross in which the individual in question is crossed with an individual known to be homozygous for a recessive trait is referred to as a:
a. parental cross.
b. dihybrid cross.
c. filial generation mating.
d. reciprocal cross.
e. testcross.

Answer 1

Test cross - because you want to see what the genotype is because you know what the test cross would be recessive and that way you can figure out the genotype.

In genetics, a test cross, first introduced by Gregor Mendel, involves the breeding of a dominant trait individual with a recessive individual, in order to determine the zygosity of the former by analysing proportions of offspring with the recessive phenotype.

The genotype that an offspring has for each of its genes is determined by the allele 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.[1]

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.