Question

1. explore: try other combinations of mouse parents. write the results of each experiment in your notes. when you have finished, answer the following questions. (note: you can refer to the parents as \pure black,\ \pure white,\ or \hybrid.\)

a. which parent combination(s) yield only white offspring?

b. which parent combination(s) yield only black offspring?

c. which parent combination(s) yield a mixture of black and white offspring?

Explanation:

To solve this, we analyze the inheritance patterns (assuming white is recessive, black is dominant, pure white is \(ww\), pure black is \(BB\), hybrid is \(Bw\)):

Part A

For only white offspring (\(ww\)), both parents must contribute \(w\). So:

• Pure white (\(ww\)) × Pure white (\(ww\)): All offspring get \(w\) from both, so \(ww\) (white).
• Pure white (\(ww\)) × Hybrid (\(Bw\)): Offspring can be \(Bw\) (black) or \(ww\) (white) → not only white.
• Hybrid × Hybrid: Offspring can be \(BB\), \(Bw\), \(ww\) → mixed.
• Pure black × any: Offspring get \(B\) → black or hybrid.

Thus, only pure white × pure white yields only white offspring.

Part B

For only black offspring, all offspring must have at least one \(B\).

• Pure black (\(BB\)) × Pure black (\(BB\)): All offspring \(BB\) (black).
• Pure black (\(BB\)) × Hybrid (\(Bw\)): Offspring \(BB\) or \(Bw\) (both black).
• Pure black (\(BB\)) × Pure white (\(ww\)): Offspring \(Bw\) (hybrid, black).
• Hybrid × Hybrid: Offspring can be \(ww\) (white) → mixed.
• Pure white × Pure white: All white.

So, combinations:

• Pure black × Pure black
• Pure black × Hybrid
• Pure black × Pure white

Part C

A mixture (black and white) requires offspring with both \(ww\) and \(B\_\) (black).

• Hybrid (\(Bw\)) × Hybrid (\(Bw\)): Offspring \(BB\) (black), \(Bw\) (black), \(ww\) (white) → mixed.
• Pure white (\(ww\)) × Hybrid (\(Bw\)): Offspring \(Bw\) (black) and \(ww\) (white) → mixed.

Other combinations (pure black × any, pure white × pure white) don’t mix.

Answer:

s:
A. Pure white × Pure white
B. Pure black × Pure black; Pure black × Hybrid; Pure black × Pure white
C. Hybrid × Hybrid; Pure white × Hybrid