Graph

In this lab we analyzed the mating of corn and soybeans in order to study the way that alleles in a genotype interact to create a phenotype. We planted corn and soybean seeds and then counted the colors of the plants that germinated. There are two main types of genotypes: homozygous and heterozygous. Using “G” to represent a dominant allele and “g” to represent a recessive allele, a heterozygous genotype would include both G and g (G/g) while a homozygous genotype would be G/G or g/g. Sometimes alleles participate in what is called incomplete or partial dominance, a Mendelian pattern in which neither allele is completely dominant and so both alleles are expressed together and neither allele is distinct from the other. While the corn that we planted yielded both green and white phenotypes, the soybeans resulted in green, yellow and a green/yellow phenotype, an example of incomplete dominance. If “G” represents a dominant green allele and “g” represents a recessive white allele, from the corn data we collected we can conclude that both corn “parent” genotypes were heterozygous G/g giving us 3 green (G/G and G/g) to 1 white (g/g). Because the soybeans show incomplete dominance, the genotypes of the soybeans are best shown using “C” for the color allele with a superscript “G” for green and “Y” for yellow. The 3 phenotype outcomes from the soybeans, 1 green (C^G/C^G) to 1 yellow (C^Y/C^Y) to 2 green/yellow (C^G/C^Y) show that the soybean “parents” must have also had a heterozygous genotype (C^G/C^Y).

To read more about other types of Mendelian inheritance patterns click here.