Which of the following describes the genotype and phenotype of parents whose child will definitely have a recessive trait?
1) Both parents are homozygous for the recessive allele and have the trait.
2) Both parents are homozygous for the recessive allele but do not have the trait.
3) Both parents are heterozygous for the recessive allele and have the trait.
4) Both parents are heterozygous for the recessive allele but do not have the trait.
I NEED HELP PLEASE :(
Both parents are homozygous for the recessive allele and have the trait is a guarantee the kids will be homozygous and have the trait.
thanks ;)
gimi all dem answers
To determine which option describes the genotype and phenotype of parents whose child will definitely have a recessive trait, we need to understand the principles of inheritance and how traits are passed from parents to offspring.
In this case, we are looking for a scenario where both parents carry the recessive allele responsible for the trait, which means they must have at least one copy of the recessive allele in their genotype. If both parents have the recessive allele, they can pass it on to their child, resulting in the child exhibiting the recessive trait.
Now, let's analyze each option:
1) Both parents are homozygous for the recessive allele and have the trait.
If both parents have the trait, it means they each have two copies of the recessive allele (aa). In this scenario, their child will definitely inherit one recessive allele from each parent and will have the trait. So, this option is a possible answer.
2) Both parents are homozygous for the recessive allele but do not have the trait.
If both parents are homozygous for the recessive allele (aa) but do not have the trait, it means that the trait is not solely determined by the recessive allele. In this case, the child may or may not inherit the trait, depending on other genetic factors. Therefore, this option does not guarantee that the child will have the recessive trait.
3) Both parents are heterozygous for the recessive allele and have the trait.
If both parents have the trait, it means they have one copy of the recessive allele and one copy of the dominant allele each (Aa). In this scenario, their child has a 25% chance of inheriting two recessive alleles and exhibiting the recessive trait, while it also has a 75% chance of inheriting at least one dominant allele and not showing the trait. Therefore, this option does not guarantee that the child will have the recessive trait.
4) Both parents are heterozygous for the recessive allele but do not have the trait.
If both parents do not have the trait, it means they each have one copy of the dominant allele and one copy of the recessive allele (Aa). In this case, the child has a 25% chance of inheriting two recessive alleles and exhibiting the recessive trait, while it has a 75% chance of inheriting at least one dominant allele and not showing the trait. This option does not guarantee that the child will have the recessive trait.
Based on the analysis, the only option that guarantees the child will definitely have a recessive trait is:
1) Both parents are homozygous for the recessive allele and have the trait.
I hope this explanation helps! Let me know if you have any further questions.