Question

2. In a certain fish, blue scales (BB) and red scales (bb) are codominant. When a fish has the

Answer 1

Answer:

a. BB

b. bb

C. Bb

Explanation:

As stated in the statement of the question, there is a species of fish in which those with the blue scale, and therefore the blue fish, have the pair of "BB" alleles, while the fish with red scales, and therefore, red fish, has the "bb" allele pair. The crossing between these fish results in a completely heterozygous, hybrid offspring. Since each member of the offspring receives an allele from each parent, the members of the offspring will present the "Bb" alleles.

However, the "BB" and "bb" alleles have codominance, which is an interaction between the alleles, where they do not establish dominance and end up being expressed together, allowing individuals to present both phenotypes at the same time. Thus, in this species of fish, the members with the "Bb" alleles have a patchwork of blue and red scales.

Answer 2

Answer:

a) BB

b) bb

c) Bb

Explanation:

Co-dominance is a type of non-mendelian genetic inheritance in which two alleles of a gene are neither dominant nor recessive over one another, hence, they form an hybrid offspring that simultaneously exhibits the traits encoded by both alleles. This is the case of the scale color gene in a certain fish. The allele for blue scales (B) and allele for red scales are codominant. Hence, they produce an hybrid with a patchwork of both blue and red colours.

Therefore, a fish with blue scale color will possess an homozygous genotype of the blue allele: BB while a fish with a red scale color will possess an homozygous genotype of the red allele: bb. Since the patchwork fish is an hybrid or heterozygous, it will contain a combination of the blue and red alleles i.e. Bb.

Because both alleles (red and blue) are codominant, both traits encoded by both alleles will be expressed at the same time in the hybrid organism (patchwork fish).