* Carrier: A carrier has one copy of the disease-causing allele (the recessive allele) and one copy of the normal allele. They don't exhibit the disease themselves but can pass on the recessive allele to their offspring.
* Homozygous recessive: A person with this genotype has two copies of the recessive allele. They will express the disease because they lack the dominant allele needed to mask the recessive trait.
Example:
* Cystic Fibrosis: The disease is caused by a recessive allele.
* Carrier: Cc (one normal allele 'C', one disease allele 'c')
* Homozygous recessive: cc (two disease alleles)
In summary:
* Carriers are heterozygous (Cc).
* Individuals with the disease are homozygous recessive (cc).
