Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEETZoologyPrinciples of Inheritance and Variation

What is the primary cause of sickle-cell anaemia at the molecular level?

Options

  1. AA deletion of a base pair in the gene
  2. BA substitution of a single base pair in the beta globin gene
  3. CAn insertion of a base pair in the beta globin gene
  4. DA duplication of the beta globin gene

Correct answer

B. A substitution of a single base pair in the beta globin gene

Step-by-step solution

This is an autosome linked recessive trait that can be transmitted from parents to the offspring when both the partners are carrier for the gene (or heterozygous). The disease is controlled by a single pair of allele, HbA and HbS . Out of the three possible genotypes only homozygous individuals for HbS (HbSHbS ) show the diseased phenotype. Heterozygous (HbAHbS ) individuals appear apparently unaffected but they are carrier of the disease as there is 50 per cent probability of transmission of the mutant gene to the

Practice Principles of Inheritance and Variation on Quantrex Academy →

More from Principles of Inheritance and Variation

Match List I with List II : List I List II A. Incomplete dominance I. Human skin colour B. Co-dominance II. Inheritance of flower colour in Antirrhinum sp. C. Pleiotropy III. Pheny 2026The sixth mutant codon of beta globin gene causing polymerization of Haemoglobin and change in RBC shape is : 2026In a population of a grasshopper species, the chromosome number of some members is 23 and some other members possess 24 chromosomes. The 23 and 24 chromosome-bearing members in thi 2026Which one of the following disorders is caused by the substitution of Glutamic acid (Glu) by Valine (Val) at the sixth position of the beta globin chain of the haemoglobin molecule 2026What is the probability of having children with 'O' blood group, where both mother and father are heterozygous for 'A' and 'B' blood group, respectively ? 2026Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R . Assertion A : In an experiment, Mendel observed that the F1 progeny plants a 2026Given below are two statements : Statement I : Down's syndrome is caused by the absence of one of the X-chromosomes. Statement II : Turner's syndrome is caused by the presence of a 2026Which of the following statements are true with reference to the sex-determination in honeybees ? A. An offspring formed from the union of a sperm and an egg, develops as a female 2026 Full Principles of Inheritance and Variation list All NEET PYQs