In chickens, the the B/b locus controls black vs. white feather color (black is dominant). The R/r locus controls red vs. orange crest color (red is dominant). Hermes is black with a red crest and Muffin is white with an orange crest. Savannah breeds Hermes and Muffin and finds that all of the offspring are black, and half have orange crests. What is Hermes's genotype? OBbRr OBbRR OBBRr OBbrr OBBRR
We can use Punnett squares to determine the possible genotypes of Hermes and Muffin and then use them to determine the probability of their offspring's genotypes.
First, let's determine Muffin's genotype. Since Muffin is white, we know that she must be homozygous recessive for the B/b locus, so her genotype is bb. Since Muffin has an orange crest, we know that she must be homozygous recessive for the R/r locus, so her genotype is rr.
Next, let's determine Hermes's genotype. Since all of their offspring are black, Hermes must be homozygous dominant for the B/b locus, so their genotype is BB or Bb. Since half of the offspring have orange crests, Hermes must have one dominant R allele and one recessive r allele, so their genotype is B_Rr or B_rr.
Since all of the offspring are black, Hermes and Muffin must have passed on a dominant B allele to all of their offspring. For the crest color, we can use a Punnett square to determine the probabilities:
| B | b
---|-----|-----
Rr | BRr | bRr
rr | Brr | brr
Since half of the offspring have orange crests, we know that half must have the genotype bRr. Therefore, Hermes's genotype must be BbRr.
Therefore, the answer is BbRr.
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