Question

What are the genotypes for each phenotype as well as the parents and the offspring for the 2 genes

Answer 1

To answer this question we need to define dominant characters over recessive ones, so we have that the parental cross is dwarf purple x tall green, and the offspring is all tall green, which indicates to us that tall and green are dominant over dwarf and purple.

Alleles

Dwarf (t)

Tall (T)

Purple (g)

Green (G)

Parental cross

Dwarf purple x Tall green

ttgg x TTGG

Obtained offspring

Tall green = TtGg

Now crossing offspring with recessive (test cross)

Tall green x Dwarf purple

TtGg x ttgg

Now to obtain the genotypes we need to to a punnet square, first, we obtain the possible gametes of this last cross

`For\text{ tall green = }T\begin{cases}G={TG} \\ g={Tg}\end{cases}t\begin{cases}G={tG} \\ g={tg}\end{cases}For\text{ Dwarf pruple = }t\begin{cases}g={tg} \\ g={tg}\end{cases}`

Now we obtain the square

As we can see there are four genotypes

TtGg= Tall green

Ttgg= Tall Purple

ttGg= Dwarf Green

ttgg= Dwarf Purple

Now For each phenotype except total recessive (dwarf purple) are more than one genotype, but the ones that this cross gives us are these. As a final note in the punnet square we obtained equal proportions of each genotype and phenotype as corresponding one to one, the represented number in the table of the exercise corresponds to the proportion of another cross, not a tester cross.

Extra genotypic combinations

Tall Green= TTGG, TTGg, TtGG, TtGg

Tall Purple= TTgg, Ttgg

Dwarf green= ttGG, ttGg