In tomatoes, the purple color of the stem dominates over the green, and the dissected leaves over the whole-edged

In tomatoes, the purple color of the stem dominates over the green, and the dissected leaves over the whole-edged ones (“potato-like”). When crossing tomato plants with purple stems and dissected leaves with plants with green stems and dissected leaves, 642 dissected purple, 202 potato purple, 620 dissected green and 214 green potato were obtained. Explain the results.

Let’s designate the gene for purple color of the tomato stem as C, and the gene for green color as c.

Let’s designate the gene that determines the formation of dissected tomato leaves as P, then the gene for whole leaves will be p.

Since the parent plants have dissected leaves, and a recessive trait is observed in the offspring – whole-edged leaves, caused by a pair of recessive genes (pp), it should be concluded that the parent tomatoes are heterozygous for the leaf shape gene (PP).

Since in the offspring there are tomatoes with both purple and green stems, it should be concluded that the parent plant with purple stems is heterozygous for the stem color gene (Cc).

Thus, tomatoes with a purple stem and dissected leaves from the parental generation will be recorded as CcPp producing sex cells cp, cp, cp and cp. Tomatoes – parents with a green stem and dissected leaves will be ccPr, the germ cells they produce – cp and cf.

The offspring from crossing these tomatoes will be represented by the following options:

tomatoes with a green stem and dissected leaves (2ssPr, ssRP);

Tomatoes with a purple stem and split leaves (3СсРР);

tomatoes with a green stem and whole leaves (ssrr);

tomatoes with a purple stem and whole leaves (Ssrr).

The resulting splitting of the form 3: 3: 1: 1 corresponds to the actual results of the condition, which confirms the correctness of the solution.

The results are attributed to independent gene inheritance.