Normally, the 6th position of the beta chain of hemoglobin is a Glutamic acid, encoded on the DNA as GAG. The sickle cell mutation has the sequence GTG, resulting in a Valine in the 6th position instead.
The allele for the sickle cell trait is codominant with the normal allele. This means that in individuals with both alleles present, both traits are expressed.
*An allele is basically the different forms a particular gene can take (describes the various genotypes/phenotypes a gene can take).* For example there is an allele of a gene which codes for haemoglobin in red blood cells, which gives them their characteristic concave shape. But there can also be a mutation in that gene, which causes a different allele to be produced which gives it a sickle-cell shape, which leads to sickle-cell anaemia.
If both parents are trait carriers the chances of them having a child WITH sickle cell is 4 to 1. Probability says, 1 will not carry the trait OR have sickle cell, 2 will be trait carriers and 1 will have it. But Keep in mind that every time you have a child its like rolling dice. I have heard of people where all four kids have the disease. and i have 2 children with the disease and 1 that's normal.
There are several types of sickle cell disease, including sickle cell anemia, sickle beta thalassemia, and sickle cell-hemoglobin C disease. These types differ based on the specific genetic mutations that affect the hemoglobin protein in red blood cells. Sickle cell anemia is the most common and severe form, where individuals have two copies of the sickle cell gene. Sickle beta thalassemia and sickle cell-hemoglobin C disease are milder forms that result from different combinations of genetic mutations. Symptoms and complications can vary among the different types of sickle cell disease.
Sickle cell trait and sickle cell disease are both genetic conditions caused by a mutation in the hemoglobin gene. Sickle cell trait means a person carries one copy of the mutated gene, while sickle cell disease means a person has two copies. The key distinction is that individuals with sickle cell trait usually do not experience symptoms, while those with sickle cell disease can have severe health issues such as pain crises, anemia, and organ damage.
codominant
codominant
The pro of sickle cell hemoglobin is that if you have only one allele for sickle cell hemoglobin and the other allele is normal, then you are immune to malaria.
The allele for the sickle cell trait is codominant with the normal allele. This means that in individuals with both alleles present, both traits are expressed.
It's not sickle-cell itself, but rather being a heterozygous carrier of the disease. People with one dominant and one recessive allele for the disease are immune to malaria without the crippling effects of having sickle-cell anemia. I don't think that it can even represent codominance, though.
Overdominance is when the heterozygote has an advantage over both the recessive and dominant homozygotes. Sickle cell disease is an example of this. When the individual is homozygous for the sickle cell allele, sickle cell disease is shown. When the the individual is homozygous for the wildtype allele, they appear normal. However, when the individual is heterozygous, he or she appears normal and will also be resistent to malaria.
Yes, the genotype SC refers to individuals who have inherited one sickle cell allele (S) and one C allele, resulting in a sickle cell trait that is different from having sickle cell disease. This genotype can lead to some symptoms similar to sickle cell disease under certain conditions.
The amino acid sequence of the sickle cell allele for hemoglobin varies from the normal allele for hemoglobin by one amino acid. The sickle cell allele for hemoglobin has valine instead of glutamic acid. When the oxygen level of the blood decreases, the hemoglobin molecules come out of solution, stick together, and form long chains that cause the red blood cells to become sickle shaped.
Sickle cell disease is an example of codominance, not heterozygous dominance. In individuals who are heterozygous for the sickle cell allele, they exhibit a milder form of the disease called sickle cell trait, which demonstrates codominance of the normal and mutant hemoglobin alleles.
Yes, individuals who are heterozygous for the sickle cell trait (having one normal hemoglobin allele and one sickle cell allele) can have greater resistance to malaria. The presence of the sickle cell allele provides some protection against the malaria parasite, as the altered shape of the red blood cells makes it less hospitable for the parasite to thrive. This selective advantage is particularly observed in regions where malaria is endemic, leading to a higher prevalence of the sickle cell trait in those populations.
Since people with the sickle cell allele trait are resistent to malaria, if malaria were eliminated there would be no change in the frequncy of sickle cell allele. This is because the presense of malaria does not have an affect on patients with the sickle cell allele trait.
If both parents have sickle cell trait, they each carry one normal allele (A) and one sickle cell allele (S). The possible genotypes for their children are AA (normal), AS (carrier), and SS (sickle cell disease), with a probability of 25% for each genotype. Therefore, the chance of having three children who are homozygous for normal red blood cells (AA) is ( (0.25)^3 ), which equals 1/64, or about 1.56%.