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 an additional copy of the chromosomes.
In the light of the above statements, choose the correct answer from the options given below :
Both Statement I and Statement II are incorrect
Analysis of Statements
Statement I: "Down's syndrome is caused by the absence of one of the X-chromosomes."
Incorrect. Down's syndrome is an autosomal disorder caused by trisomy (an additional copy) of chromosome 21, not the absence of an X-chromosome.
Statement II: "Turner's syndrome is caused by the presence of an additional copy of the chromosomes."
Incorrect. Turner's syndrome is a sex-chromosome disorder caused by monosomy—specifically, the absence (loss) of one of the X-chromosomes in females, resulting in a $45,X$ karyotype.
Interestingly, the question text has swapped the descriptions for both syndromes! Since both statements are factually wrong, we can confidently identify the correct choice.
Correct Option
Option 4 (Both Statement I and Statement II are incorrect)
Similar Questions
- Which 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 ?
- 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. Phenylketonuria disease in humans D. Polygenic inheritance IV. ABO blood groups
Choose the correct answer from the options given below : - Which 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 (queen or worker).
B. An unfertilized egg develops as a male by parthenogenesis.
C. A male has half the number of chromosomes than that of a female.
D. Males produce sperms by meiosis.
E. Honeybees have a haplodiploid sex-determination system.
Choose the correct answer from the options given below : - In which animal do haploid cells divide mitotically to produce gametes ?
- What is the probability of having children with 'O' blood group, where both mother and father are heterozygous for 'A' and 'B' blood group, respectively ?
- The sixth mutant codon of beta globin gene causing polymerization of Haemoglobin and change in RBC shape is
- In 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 this species are ________ .
- Given 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 are all tall and none are dwarf.
Reason R : Stem height is a contrasting trait, with tall being dominant and dwarf being recessive.
In the light of the above statements, choose the most appropriate answer from the options given below : - For a person with blood group 'O', which of the following is not a possible combination of parents' blood group genotypes ?
Important Questions from Genetics
- Which 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 ?
- 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. Phenylketonuria disease in humans D. Polygenic inheritance IV. ABO blood groups
Choose the correct answer from the options given below : - Which 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 (queen or worker).
B. An unfertilized egg develops as a male by parthenogenesis.
C. A male has half the number of chromosomes than that of a female.
D. Males produce sperms by meiosis.
E. Honeybees have a haplodiploid sex-determination system.
Choose the correct answer from the options given below : - In which animal do haploid cells divide mitotically to produce gametes ?
- What is the probability of having children with 'O' blood group, where both mother and father are heterozygous for 'A' and 'B' blood group, respectively ?
