Question

If a person is considered a carrier for a trait, are they heterozygous or homozygous at the locus for the mutated gene?

Answer 1

The person is said to be heterozygous at the locus of the mutated gene.

Heterozygous means that this person has one normal gene and the other mutuated gene.

If the carrier, the mutated gene is the recessive gene, than the person does not show any signs or symptoms of the mutated gene and has a normal conditions just like a person who is not a carrier of the mutated gene.

Example of mutated recessive gene is sickle cell anemia. Here, the heterozygous person has normal health conditions even if he is the carrier of sickle cell anemia, as due to the fact that he has one unmutated gene at his locus (which is dominant).

If the mutated gene is a dominant then this is enough bring out the conditon in the patient. Example of this is Huntington disease.

Homozygous conditon is where both of the genes are mutated and this person shows the signs and symptoms of the condition.

Homozygous unmutated gene person is neither the carrier nor is the sufferer of the genetic condition. He will have a normal healthy body condition.