What are the expected phenotypic ratios from the following cross:
Tt Rr YY Aa × Tt rr Yy Aa,
where T = tall, t = dwarf, R = round, r = wrinkled, Y = yellow, y = green, A = axial, a = terminal; T, R, Y, and A are dominant alleles. (Note: multiplication method or forked-line method.
Using the multiplication method:
1. First, write out the alleles for each parent:
Tt Rr YY Aa × Tt rr Yy Aa
TRYa TrYa TyAA trYa
2. Create a Punnett square and fill in the boxes by combining the alleles from each parent:
| TRYa | TrYa | TyAA | trYa |
---|---|---|---|---|
tRya | TtRrYYAa | TtRrYYaa | TtRryyAa | TtRryyaa |
trYa | TtrrYYAa | TtrrYYaa | TtryyAa | Ttryyaa |
tyAA | TtRrYyAA | TtRrYyaa | TtRryyAA | TtRryyaa |
trya | TtrryyAa | Ttrryyaa | TtryyAa | Ttryyaa |
3. Count the number of each possible genotype:
TtRrYYAa - 1
TtRrYYaa - 1
TtRryyAa - 1
TtRryyaa - 1
TtrrYYAa - 1
TtrrYYaa - 1
TtryyAa - 1
Ttryyaa - 1
TtRrYyAA - 1
TtRrYyaa - 1
TtRryyAA - 1
TtRryyaa - 1
TtrryyAa - 1
Ttrryyaa - 1
TtryyAA - 1
Ttryyaa - 1
4. Convert the genotypic counts to phenotypic ratios:
Tall, Round, Yellow, Axial - 4/16 or 1/4 or 25%
Tall, Round, Yellow, Terminal - 4/16 or 1/4 or 25%
Tall, Round, Green, Axial - 2/16 or 1/8 or 12.5%
Tall, Round, Green, Terminal - 2/16 or 1/8 or 12.5%
Tall, Wrinkled, Yellow, Axial - 2/16 or 1/8 or 12.5%
Tall, Wrinkled, Yellow, Terminal- 2/16 or 1/8 or 12.5%
Tall, Wrinkled, Green, Axial - 1/16 or 6.25%
Tall, Wrinkled, Green, Terminal - 1/16 or 6.25%
Therefore, the expected phenotypic ratios are: 25% Tall, Round, Yellow, Axial; 25% Tall, Round, Yellow, Terminal; 12.5% Tall, Round, Green, Axial; 12.5% Tall, Round, Green, Terminal; 12.5% Tall, Wrinkled, Yellow, Axial; 12.5% Tall, Wrinkled, Yellow, Terminal; 6.25% Tall, Wrinkled, Green, Axial; 6.25% Tall, Wrinkled, Green, Terminal.
I can explain how to use the multiplication or forked-line method to determine the expected phenotypic ratios from this cross.
To use the multiplication method, you would simply multiply the probabilities of each parent passing on a specific allele for each trait. The resulting probabilities can then be used to determine the expected phenotypic ratios.
To use the forked-line method, you would draw a forked-line diagram representing the possible gametes that each parent can produce. Then, you would combine the gametes from each parent to determine the possible genotypes of the offspring. The resulting genotypic ratios can then be used to determine the expected phenotypic ratios using knowledge of the dominant and recessive alleles.
I hope this explanation helps. Remember, academic honesty is important and cheating can have serious consequences. It's always better to try to understand the material and do the work yourself.
As an AI language model, I am incapable of cheating. However, I agree that academic honesty is important and encourage everyone to learn and work hard to understand the material.
To determine the expected phenotypic ratios from the given cross, we can use the multiplication method or the forked-line method. Let's use the multiplication method for this example.
Step 1: Write down the genotypes of each parent:
Parent 1: Tt Rr YY Aa
Parent 2: Tt rr Yy Aa
Step 2: Identify the alleles from each parent for each trait.
For each trait in the parents, we have the following alleles:
- Parent 1: T, t, R, r, Y, Y, A, a
- Parent 2: T, t, -, r, Y, y, A, a
Step 3: Set up a Punnett square by crossing the alleles from each parent:
T t
T TT Tt
t Tt tt
R r
R RR Rr
r Rr rr
Y y
Y YY Yy
y Yy yy
A a
A AA Aa
a Aa aa
Step 4: Determine the possible combinations of alleles for each trait in the offspring.
Combining the alleles from the Punnett square, we obtain the following genotypes for each trait:
- Tall/dwarf:
- TT, Tt, Tt, tt (phenotypic ratio: 3:1)
- Round/wrinkled:
- RR, Rr, Rr, rr (phenotypic ratio: 3:1)
- Yellow/green:
- YY, Yy, Yy, yy (phenotypic ratio: 3:1)
- Axial/terminal:
- AA, Aa, Aa, aa (phenotypic ratio: 3:1)
Step 5: Calculate the overall phenotypic ratios by multiplying the individual ratios of each trait.
Since all the phenotypic ratios are 3:1, we can multiply them together to get the overall phenotypic ratio:
3:1 * 3:1 * 3:1 * 3:1 = 81:1
Therefore, the expected phenotypic ratio is 81:1.
Note: The forked-line method is another approach to determine the expected phenotypic ratios, but it requires drawing multiple lines for each trait and counting the possible combinations. It is more time-consuming but can be used as an alternative method.