Which is the most likely explanation for a child exhibiting a heritable trait that neither parent exhibits?
A. The trait is recessive, and the child inherited a recessive allele from each parent.
B. The parents have recessive alleles, and the child inherited a dominant allele.
C. A mutation occurred, and the child exhibits a new trait due to the mutation.
D. A grandparent exhibits the trait, and the child inherited it directly from that person.
C. A mutation occurred, and the child exhibits a new trait due to the mutation.
The most likely explanation for a child exhibiting a heritable trait that neither parent exhibits is option C: A mutation occurred, and the child exhibits a new trait due to the mutation.
To determine the most likely explanation for a child exhibiting a heritable trait that neither parent exhibits, we can consider the principles of inheritance and genetic variation.
Option A suggests that the trait is recessive, and the child inherited a recessive allele from each parent. This is a possibility if both parents carry a single copy of the recessive allele, which would not be expressed in their phenotype, but can be passed on to their child. However, it is important to note that if both parents exhibit the same trait in their phenotype, it is unlikely that the trait is recessive.
Option B suggests that the parents have recessive alleles, and the child inherited a dominant allele. In this scenario, the child would exhibit the trait if they inherited a dominant allele from one parent and a recessive allele from the other. However, if neither parent exhibits the trait, it is unlikely that they both carry a recessive allele for the trait.
Option C suggests that a mutation occurred, and the child exhibits a new trait due to the mutation. Mutations can arise spontaneously and result in new traits that are not present in either parent. This option is a possibility if there is evidence of a genetic mutation leading to the heritable trait in question.
Option D suggests that a grandparent exhibits the trait, and the child inherited it directly from that person. This option implies that there is a skipped generation, where the trait is present in a previous generation but not in the parents. It is possible for a trait to skip a generation and be inherited directly from a grandparent.
In conclusion, the most likely explanation for a child exhibiting a heritable trait that neither parent exhibits would be either option C (a mutation occurred, and the child exhibits a new trait due to the mutation) or option D (a grandparent exhibits the trait, and the child inherited it directly from that person). Additional genetic testing or analysis would be required to determine the exact cause of the trait in question.