An additional pleiotropic phenotype associated with the HbS allele is resistance to malaria. Using the comparison method above, show which of the two alleles is dominant and which is recessive when considering the phenotypes of:1.) sickle cell syndrome2.) malarial resistanceHbS = the mutant sickle cell allele of Beta-globin HbA = the non-mutant allele for adult Beta-globin
Added by Silvia H.
Step 1
- HbS: the mutant sickle cell allele of Beta-globin, which causes sickle cell syndrome. - HbA: the non-mutant allele for adult Beta-globin, which produces normal red blood cells. Show more…
Show all steps
Your feedback will help us improve your experience
Josee Pacheco and 61 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
A and S are two alleles of the ̠-globin gene, as shown in the graph below. Match the dominance relations of allele A and S at each level of analysis. (Select I,II, III or IV) *Note: I refers only to the "Red blood cell concentration at high altitude" phenotype and not the "Red blood cell shape at high altitude" phenotype. S is dominant, A is recessive A is dominant, S is recessive A and S are codominant A and S show incomplete dominance
Josee P.
Sri K.
PROBLEM #2. Sickle-cell anemia is an interesting genetic disease. Normal homozygous individuals (SS) have normal blood cells that are easily infected with the malarial parasite. Thus, many of these individuals become very ill from the parasite and many die. Individuals homozygous for the sickle-cell trait (ss) have red blood cells that readily collapse when deoxygenated. Although malaria cannot grow in these red blood cells, individuals often die because of the genetic defect. However, individuals with the heterozygous condition (Ss) have some sickling of red blood cells, but generally not enough to cause mortality. In addition, malaria cannot survive well within these "partially defective" red blood cells. Thus, heterozygotes tend to survive better than either of the homozygous conditions. If 9% of an African population is born with a severe form of sickle-cell anemia (ss), what percentage of the population will be more resistant to malaria because they are heterozygous (Ss) for the sickle-cell gene?
Shaiju T.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD