A normal woman whose father was haemophilic, marries a normal man. What percentage of the progeny is affected?
Important Questions on Heredity and Variation
(i) Haemophilia is a sex-linked recessive disease.
(ii) Down's syndrome is due to aneuploidy.
(iii) Phenylketonuria is an autosomal recessive gene disorder.
(iv) Sickle cell anaemia is an X-linked recessive gene disorder.
Statement I : All the three types of allosomal genes - linked, linked and linked are present only in male human being.
Statement II : Only linked and not linked genes are present in female human being.
The correct option among the following is
Statement (S): The heterozygous individuals for sickle-cell anaemia express disease phenotype and also carriers of the disease.
Reason (R): genotype individuals are resistant to severe effects of malaria.
The correct answer is
The following family tree traces the occurrence of a rare genetic disease. The filled symbols signify the individuals with the disease, whereas the open symbols signify healthy individuals.
Based on this information, the disease is most likely to be:
