given the following phenotypic reactions, determine the most probable genotype:

anti-d anti-c anti-e anti-c anti-e
+ + 0 + +

r0r
rzry
r1r
r2r

Question

given the following phenotypic reactions, determine the most probable genotype:

anti-d anti-c anti-e anti-c anti-e
+ + 0 + +

r0r
rzry
r1r
r2r

Accepted Answer

{ "quality": "clear", "question_count": 1, "skills_matched": [ "step_cot", "multiple_choice_formatter", "explain_then_answer", "tutor", "mastery_adaptive_brevity" ], "needs_drawing": false, "concepts_used": [ "Wiener Nomenclature", "Rh Genotype Frequencies" ], "new_concepts": [], "current_concepts": [ "Wiener Nomenclature", "Rh Genotype Frequencies", "Rh Blood Group System" ] } ## Identify antigens from phenotypic reactions Using the *Wiener Nomenclature* knowledge point $$ \begin{aligned} &\text{Anti-D: } + \implies \text{D antigen present} \ &\text{Anti-C: } + \implies \text{C antigen present} \ &\text{Anti-E: } 0 \implies \text{E antigen absent} \ &\text{Anti-c: } + \implies \text{c antigen present} \ &\text{Anti-e: } + \implies \text{e antigen present} \end{aligned} $$ The phenotype is $ \text{D+, C+, E-, c+, e+} $. ## Determine possible genotypes Using the *Wiener Nomenclature* knowledge point $$ \begin{aligned} &\text{Haplotypes present must combine to yield: } \text{D, C, c, e (no E)} \ &\text{Since D is present, at least one haplotype must be Rh-positive: } R^1 (DCe), R^0 (Dce), \text{ or } R^z (DCE) \ &\text{Since E is absent, } R^z \text{ and } R^2 \text{ are excluded as major contributors.} \ &\text{Since C and c are both present, and e is present:} \ &\text{Combination 1: } R^1 (DCe) \text{ and } r (dce) \implies R^1r \ &\text{Combination 2: } R^0 (Dce) \text{ and } r' (dCe) \implies R^0r' \end{aligned} $$ ## Evaluate genotype frequencies Using the *Rh Genotype Frequencies* knowledge point $$ \begin{aligned} &\text{Frequency of } R^1 \approx 0.42, \quad r \approx 0.37 \ &\text{Frequency of } R^0 \approx 0.04, \quad r' \approx 0.01 \ &\text{Probability of } R^1r = 2 \times 0.42 \times 0.37 \approx 0.311 \quad (31.1\%) \ &\text{Probability of } R^0r' = 2 \times 0.04 \times 0.01 \approx 0.0008 \quad (0.08\%) \ &\text{Therefore, } R^1r \text{ is the most probable genotype.} \end{aligned} $$ ## Address student query regarding r'r' Using the *Wiener Nomenclature* and *Rh Genotype Frequencies* knowledge points $$ \begin{aligned} &\text{Haplotype } r' \text{ represents } dCe. \ &\text{Genotype } r'r' \text{ would result in the phenotype: } \text{D-, C+, E-, c-, e+}. \ &\text{This is incorrect because the patient is D-positive (Anti-D +) and c-positive (Anti-c +).} \end{aligned} $$

(A) R0r

(B) RZry

(C) R1r

(D) R2r

{ "subject": "Natural Science", "question_type": "Multiple Choice", "knowledge_point": [ "Natural Science", "Biology", "Immunohematology" ] }

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QUESTION IMAGE

Question

Explanation:

Identify antigens from phenotypic reactions

Determine possible genotypes

Evaluate genotype frequencies

Address student query regarding r'r'

Answer: