What is the expression of allele G in individuals affected by the genetic disease X.367G?

The expression of allele G in individuals affected by the genetic disease X.367G is best described by the option that states it is expressed in homozygous individuals. This suggests that the genetic disease manifests when an individual carries two copies of the allele G, indicating that the disease is likely recessive in nature.

In many genetic conditions, recessive alleles need to be present in two copies (one from each parent) for the phenotype associated with the disease to be expressed. In this case, homozygous individuals (those with two copies of allele G) would demonstrate symptoms or traits of the associated genetic disease.

In contrast, heterozygous individuals (those with one copy of G and one copy of the normal allele) would generally not express the disease phenotype because the dominant normal allele may mask the effects of the recessive disease-causing allele. The option that indicates expression in all individuals fails to account for the typical genetic pattern observed with recessive diseases, where the presence of one normal allele is sufficient to prevent the disease from manifesting. Furthermore, the notion of expression only in carriers implies that those individuals with one copy of the allele would show symptoms, which contradicts the typical understanding of recessive inheritance. Therefore, the conclusion