The patient with sickle cell anaemia has red blood cells with an abnormal form of hemoglobin.The gene for haemoglobin exists in two forms:HN= dominant allele for normal hemoglobin.Hs= recessive allele for abnormal hemoglobin.If 50% of the children of a couple have sickle cell anaemia,then the genotype of the couple would be:
Correct answer: A. HNHs,HS HS
- A. HNHs,HS HS
- B. HNHN ,HN HN
- C. HNHN,HS HS
- D. HNHs,HNHS
Explanation
Option A suggests one parent is a carrier (heterozygous) and the other has two recessive alleles, which would result in 50% of the children having sickle cell anaemia. So option A is correct. The other options don't give tge required probability of phenotype.
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About Mendel's Laws of Inheritance
Mendelian inheritance explains how alleles separate into gametes and assort during reproduction, producing predictable genotype and phenotype ratios. Questions cover dominance, recessiveness, homozygous and heterozygous conditions, the laws of segregation and independent assortment, monohybrid and dihybrid crosses, test crosses and the limits caused by linked genes.
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