The plant is heterozygous for green leaves. Green (G) is dominant over variegated (g).

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Here are the solutions to the genetics problems:

3.1.1
The plant is heterozygous for green leaves. Green (G) is dominant over variegated (g).
The genotype is $\boxed{\text{Gg}}$ .

3.1.2
The plant (Gg) undergoes self-pollination (Gg x Gg).
The Punnett square for Gg x Gg is:

	G	g
G	GG	Gg
g	Gg	gg

The genotypic ratio is 1 GG : 2 Gg : 1 gg.
The phenotypic ratio is 3 Green (GG, Gg) : 1 Variegated (gg).
Total offspring = 64.

a) Number of plants that will have variegated leaves:

Determine the proportion of variegated offspring (gg).
$P(\text{gg}) = \frac{1}{4}$
Calculate the number of variegated plants.
$\text{Number of variegated plants} = \frac{1}{4} \times 64 = 16$
Expected number of plants with variegated leaves: $\boxed{\text{16}}$

b) Number of plants that will be heterozygous for green leaves:
Determine the proportion of heterozygous offspring (Gg).
$P(\text{Gg}) = \frac{2}{4} = \frac{1}{2}$
Calculate the number of heterozygous plants.
$\text{Number of heterozygous plants} = \frac{1}{2} \times 64 = 32$
Expected number of plants heterozygous for green leaves: $\boxed{\text{32}}$

c) Number of plants that will be homozygous:
Determine the proportion of homozygous offspring (GG or gg).
$P(\text{homozygous}) = P(\text{GG}) + P(\text{gg}) = \frac{1}{4} + \frac{1}{4} = \frac{2}{4} = \frac{1}{2}$
Calculate the number of homozygous plants.
$\text{Number of homozygous plants} = \frac{1}{2} \times 64 = 32$
Expected number of homozygous plants: $\boxed{\text{32}}$

2.5
Symbols: T = normal allele, t = recessive Tay-Sachs allele.
A couple are both heterozygous for Tay-Sachs (Tt x Tt).
The Punnett square for Tt x Tt is:

T t
T TT Tt
t Tt tt

The genotypic ratio is 1 TT : 2 Tt : 1 tt.
Tay-Sachs disorder is recessive, so a child with the disorder has the genotype tt.
Determine the proportion of offspring with Tay-Sachs (tt).
$P(\text{tt}) = \frac{1}{4}$
Convert the proportion to a percentage.
$\text{Percentage chance} = \frac{1}{4} \times 100\% = 25\%$
The percentage chance of having a child with Tay-Sachs disorder is $\boxed{\text{25\%}}$ .

2.6
One in every 27 people in the population group has at least one allele for Tay-Sachs (Tt or tt).
Total sample size = 360,000 people.
Identify the proportion of people with at least one allele for Tay-Sachs.
$\text{Proportion} = \frac{1}{27}$
Calculate the expected number of people with the allele in the sample.
$\text{Number of people with allele} = \frac{1}{27} \times 360\,000$ $\text{Number of people with allele} = 13\,333.33$
Since the number of people must be a whole number, we round to the nearest whole number.
$\text{Number of people with allele} \approx 13\,333$
You expect $\boxed{\text{13,333}}$ people to have the allele for Tay-Sachs.

The plant is heterozygous for green leaves. Green (G) is dominant over variegated (g).

Step-by-step solution

Determine the proportion of variegated offspring (gg).

Calculate the number of variegated plants.

Determine the proportion of heterozygous offspring (Gg).

Calculate the number of heterozygous plants.

Determine the proportion of homozygous offspring (GG or gg).

Calculate the number of homozygous plants.

Determine the proportion of offspring with Tay-Sachs (tt).

Convert the proportion to a percentage.

Identify the proportion of people with at least one allele for Tay-Sachs.

Calculate the expected number of people with the allele in the sample.

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