A chart shows allele combinations for brown/blonde hair: Father’s Mother, Bb; Mother’s Mother, BB; Mother, Bb; Child, bb. What allele combinations are missing?

Answer 1

To analyze the allele combinations for brown/blonde hair based on the information you've provided, let's first break down what we have:

• Father’s Mother: Bb (This means she carries one brown hair allele (B) and one blonde hair allele (b).)
• Mother’s Mother: BB (This means she carries two brown hair alleles.)
• Mother: Bb (This means she carries one brown hair allele and one blonde hair allele.)
• Child: bb (This means the child has inherited two blonde hair alleles.)

In order for the child to be bb, they must inherit a b allele from both parents. Let's deduce the missing allele combinations:

1. Father’s Alleles: We don't have the father's allele combination specified. Since the child is bb, the father must possess at least one b allele. His possible combinations could be either Bb (carrier of blonde) or bb (blonde).

2. Allele combinations for possible parents:

   • Father: Bb or bb
   • Child: bb is already provided.
   • Mother: Bb is already provided.

Now, let’s summarize potential combinations:

• If the father is Bb:

  • Possible allele combinations when pairing with the mother (Bb):
    • BB (not possible since the child is bb)
    • Bb (possible, leading to BB, Bb, and bb offspring)
    • bb (possible, leading to bb offspring)

• If the father is bb:

  • When pairing with the mother (Bb):
    • bb (the only outcome here since the father's only allele is b)

As per the combinations:

• Missing combinations for the father is specifically his allele combination if not provided, which could be Bb or bb. If you're looking for the full picture, we should also take into account any other possible combinations in the broader family tree, but based on this immediate scenario, we've covered what can be inferred.

So to answer your original question: Missing allele combinations specifically refer to the father's allele: Bb or bb. Both must include at least one b allele to fit with the child being bb.

If you're looking for potential combinations across generations, please clarify further!