Bateson and Punnett crossed two white-flowered lines and saw all purple flowers in the F1 generation. They concluded this was an example of complementary gene interactions because a cross of the F1 plants yielded what ratio in the F2 generation?

Step 1

A pair of genes can often work together to create a specific genotype it is called complementary interaction.

If both dominant alleles when present together each other are called complementary genes and produce a different phenotype.

Step 2

According to Bateson and Punnett, when two such white varieties of pea were crossed, then in F1 generation offspring were found purple-colored flowers but in F2 generation 9 were the purple flower and 7 were the white flower. So, it is an example of complementary gene interaction.

The production of purple color flower both complementary C or P genes is necessary to remain present. In the absence of either of these genes, C or P the color of the flowers were white.

Thus, genes C and P interact and the presence of both is essential for purple color flower. These types of genes in which one gene complement on another gene are called complementary gene interaction.

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Step 3

If both gene loci have homozygous alleles and both of them produce identical phenotypes the F2 ratio become 9:7 instead of 9:3:3:1

In such a case, the genotype ccPP, ccPp, ccpp, Ccpp produce one phenotype.

In pea plant presence of genes CC, cc,...

Explanation: