Which of the following describes the genotype and phenotype of parents whose child will definitely have a recessive trait?
B
A
B
D
C
Thank for no hêlp
^^is correct
To determine the genotype and phenotype of parents whose child will definitely have a recessive trait, you need to understand the underlying principles of inheritance and the laws of genetics.
In this case, we are dealing with a recessive trait, which means that the trait is only expressed when an individual receives two copies of the recessive allele. In terms of notation, the dominant allele is typically represented by a capital letter, while the recessive allele is represented by a lowercase letter.
Let's assume that the recessive trait is represented by the letter 'r'. To determine the genotype and phenotype of parents whose child will definitely have a recessive trait, both parents must carry at least one copy of the recessive allele (rr), either as homozygous recessive (rr) or heterozygous (Rr).
Here are the possible combinations that would result in a child definitely having a recessive trait:
1. Homozygous recessive x Homozygous recessive (rr x rr): In this case, both parents have two copies of the recessive allele, guaranteeing that their child will also have two copies.
2. Homozygous recessive x Heterozygous (rr x Rr): In this scenario, one parent has two copies of the recessive allele, while the other parent carries one copy of the recessive allele and one copy of the dominant allele. Each child has a 50% chance of inheriting the recessive allele from the heterozygous parent, resulting in a recessive trait.
3. Heterozygous x Heterozygous (Rr x Rr): Both parents carry one copy of the recessive allele and one copy of the dominant allele. Each child has a 25% chance of inheriting two copies of the recessive allele, resulting in a recessive trait.
It's important to note that if both parents have at least one dominant allele (RR or Rr), their child will not have a recessive trait. The recessive trait will only manifest if both parents carry at least one copy of the recessive allele (rr).
To determine the genotype and phenotype of parents, it is essential to understand the family history, observe offspring and their traits through several generations, and potentially perform genetic testing.