Question

the dorsal fin color on a species of whales has five distinguishable phenotypes that consist of two different traits:

• trait 1: the dorsal fin color can be black, partially gray, or gray.
• trait 2: the dorsal fin can have white spots called white blazes, or not.

scientists observe a population of these whales and record the phenotypes of each. their observations are recorded in the table.
based on their observations, the scientists conclude:

• the color of the dorsal fin is a sex - linked trait, with black (x^g) incompletely dominant to gray (x^g).
• the white blaze trait exhibits a complete dominance inheritance pattern, with presence (b) dominant to absence (b).

move the correct chromosomal pairs with alleles into the karyotype so that it represents a male with a dorsal fin that is black with white blaze.

• use only one chromosomal pair in each blank box you fill in.
• you may not need to use all the chromosomal pairs.
• there may be more than one correct answer.

which chromosome pair(s) would work in box a?

Explanation:

Step1: Analyze the traits

The dorsal - fin color is a sex - linked trait. Males have one X and one Y chromosome. The white - blaze trait is autosomal (since it's not mentioned as sex - linked). For a male with a black dorsal fin (X^G) and white blaze (B is dominant for white blaze, so genotype for white blaze can be BB or Bb).

Step2: Consider autosomal chromosomes

For the autosomal white - blaze trait, the possible genotypes for a male with white blaze are BB or Bb. Looking at the autosomal chromosome pairs (pairs 1 - 17 in the karyotype map), pair 2 (with alleles B and B) and pair 4 (with alleles B and b) are relevant for the white - blaze trait.

Answer:

Pair 2, Pair 4