Question

Organisms with the genotypes aabbccdd and aabbccdd are crossed. What are the expected proportions of the following progeny?

Answer 1

Answer:

a) $\frac{27}{64}$

b)$\frac{1}{32}$

c) $\frac{27}{64}$

d) $\frac{3}{64}$

Explanation:

The correct question is

Organisms with the genotypes AABbCcDd and AaBbCcDd are crossed. What are the expected proportions of the following progeny?

a. A_B_C_D_

b. AabbCcDd

c. a phenotype identical to either parent

d. A_B_ccdd

Solution

In such question the probability for each allele pair is to be determines separately

For instance,

AA * Aa will produce AA, Aa, AA, Aa this means that all the the probability of getting both AA and Aa is $\frac{1}{2}$

Like wise when Bb and Bb are crossed, BB, Bb, Bb, and bb are produced. So the probability of getting dominant trait i.e BB or Bb is $\frac{3}{4}$ and recessive trait i.e bb is $\frac{1}{4}$

Chance to get homozygous bb only or BB only is $\frac{1}{4}$

and chance of getting Bb is  $\frac{1}{2}$

Like Bb and Bb cross, the same will be the probabilities for Cc and Cc cross and Dd and Dd cross

Part A)

$\frac{1}{4} * \frac{3}{4} * \frac{3}{4} * \frac{3}{4} \\= \frac{27}{64}$

Part B)

$\frac{1}{4} * \frac{1}{2} * \frac{1}{2}* \frac{1}{2}\\= \frac{1}{32}$

Part C)

$\frac{1}{4} * \frac{3}{4} * \frac{3}{4} * \frac{3}{4} \\= \frac{27}{64}$

Part D)

$\frac{3}{4} * \frac{1}{4} * \frac{1}{4} * \frac{1}{4} \\= \frac{3}{64}$