1. Long hair is recessive to short hair in the Saharan pygmy mouse. If a true br

Question

1. Long hair is recessive to short hair in the Saharan pygmy mouse. If a true breeding short hair animal mates with a long hair animal, what would you expect the offspring hair to be like?

a. All long hair

b. Approximately 25% long hair

c. All short hair

d. Approximately 75% long hair

e. Approximately 50:50 short to long hair

2. Out of sheer frustration for their Academic stubbornness and ignorance, Mendel decides to go on a tour of the finest European Universities to sell his hypothesis concerning inheritance. During this period, he leaves his technician Horace in charge. However, on his return, he finds that Horace had been paying a little too much attention to the Monastery Pilsners and had let things get out of hand in the garden. He knows that yellow (G) seeds are dominant over green (g), smooth seeds (W) are dominant over wrinkled seeds (w) and tall plants (D) are dominant over dwarf plants (d).

Mendel takes a tall plant with yellow seeds and breeds it to a dwarf plant with green seeds. Out of over 200 offspring, all are tall whereas about half have yellow seeds. What can he conclude is the genotype of this plant?

a. The plant is genotype DD/Gg

b. The plant is genotype dd/gg

c. The plant is genotype DD/GG

d. The plant is genotype Dd/Gg

e. An additional cross is needed to determine both genotypes.

Explanation / Answer

1) The answer will be all short hair (Option c).

Explanation: True breeding trait is homozygous for the trait. Let assume, genotype of true breeding short hair mouse is HH & genotype of recessive long hair mouse is hh. The genotype & phenotype of the offspring is shown in the following Punnet square.

2) The answer will be genotype of tall plant with yellow seeds (Parent plant) is DD/Gg (Option a).

Explanation: To obtain offspring which are all tall, genotypes of the offspring must be DD or Dd. Now, if we consider the genotype of dwarf plant, it is dd. So, one parental plant has homozygous recessive trait. Now to obtain offspring with tall characteristic from this dwarf plant, it has to breed with tall plant with homozygous trait (DD). If we breed dwarf plant with tall plant with heterozygous trait (Dd), then half the offspring will be dwarf. Following Punnet squares will prove it.

Now if we consider the color trait, 50% of the plants have yellow seeds (dominant) & other 50% have green seeds (recessive). We know that if we cross with homozygous recessive trait with heterozygous dominant trait we will have offspring with 50% dominant trait & 50% recessive trait. So, the seed color genotype must be Gg. Following Punnet square will prove it.

So, the parental plant with tall & yellow seed characteristics has genotype DD/Gg.

h h H Hh (Genotype heterozygous for dominant short hair trait) Hh (Genotype heterozygous for dominant short hair trait) H Hh (Genotype heterozygous for dominant short hair trait) Hh (Genotype heterozygous for dominant short hair trait)

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.