Populations of the grasshopper Vandiemenella viatica possess different chromosomal fusions and inversions. Grasshoppers that are heterozygous for different chromosomal rearrangements have reduced fitness. What would you expect to observe if you investigated the genotypes of grasshoppers in a recently merged population?

The options

a. New combinations of genes yielding genotypes of greater fitness

b. Few heterozygotes because of underdominance

c. Frequency-dependent selection, leading to fluctuations in fitness

d. Heterozygotes with greater fitness, owing to overdominance

e. A random assortment of genotypes because of genetic drift

The CORRECT ANSWER IS b.

b. Few heterozygotes because of under dominance

Explanation:

In genetics, underdominance (at times called "negative overdominance") is the opposite of overdominance.

It is the selection against the heterozygote, that leads to disruptive selection and divergent genotypes. It occurs in cases of inferior and reduced fitness (As in our case study, it is the different chromosomal fusions and inversions)

of the heterozygotic genotype to the dominant or recessive homozygotic genotype. It is unstable as it causes fixation of either allele.

Another example is the African butterfly species Pseudacraea eurytus, which makes use of Batesian mimicry to avoid predation. This species carries two alleles that gives a coloration that is alike to a different local butterfly species that is harmful to its predator. The butterflies who are heterozygous for this trait are observed to be intermediate in coloration and thus encounter an higher risk of predation and a decrease in the total fitness.

the scientific method.

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex