Can someone please tell me if this paragraph makes any sense at all? I feel like I contradict myself, as I do not understand the subject very well. Thank you.
"Since neither of the parents in the pedigree has the genetic disorder (as indicated by their non-darkened shapes, which represent individuals that are unaffected by the disorder), they must both be recessive for the specific trait. This means that both genes are the recessive gene for the trait. Therefore, the genotype of both parents is heterozygous (Rr and Rr—dominant gene R and recessive gene r), and the trait itself is recessive, since neither parent has the disorder. If the disorder were dominant, then one of the parents would have to carry it. Since this is not the case, however, we may conclude that both parents are heterozygous carriers, and that the trait itself is recessive. Both parents are also carriers of the disorder, meaning that they are heterozygous for the inherited disorder but do not show symptoms of the disorder. The only offspring that is affected by the genetic disorder is offspring number 3, as indicated by her darkened shape. Her genotype is homozygous recessive (rr), meaning that she has the same two alleles for the gene, since she is a carrier of two of the recessive genes of that particular trait. The other offspring do not have darkened shapes, and therefore we may conclude that they are not affected by the specific genetic disorder, like offspring number three is."
Please refer to your post named Biology, which I saw first.
Sra
Yes, the paragraph makes sense. It explains the genetic inheritance pattern of a specific trait in a pedigree. Let me break it down for you:
The paragraph is discussing a pedigree, which is a visual representation of the genetic relationships within a family. In this pedigree, the parents do not have the genetic disorder, indicated by their non-darkened shapes. Since the disorder is not present in either parent, it implies that the disorder is recessive.
Next, it explains that both parents must be recessive for the specific trait because they do not have the disorder. This means that both parents carry two copies of the recessive gene for the trait (represented as Rr and Rr). Therefore, the genotype of both parents is heterozygous.
The paragraph then clarifies that if the disorder were dominant, one of the parents would have to carry it, but since neither parent does, it confirms that the disorder is recessive. It concludes that both parents are heterozygous carriers, meaning they carry one copy of the recessive gene but do not show symptoms of the disorder.
Moving on, the paragraph identifies one specific offspring, referred to as "offspring number 3," who is affected by the genetic disorder, as indicated by her darkened shape in the pedigree. The genotype of this offspring is homozygous recessive (rr), meaning she inherited two copies of the recessive gene for the trait.
Finally, the paragraph states that the other offspring in the pedigree do not have darkened shapes, meaning they are not affected by the specific genetic disorder, unlike offspring number three.
In summary, the paragraph explains the pattern of inheritance and genotypes of the parents and offspring in relation to a specific genetic disorder, as depicted in a pedigree.