A man and a woman, who do not show any apparent signs of a certain inherited disease, have seven children (2 daughters and 5 sons). Three of the sons suffer from the given disease but none of the daughters are affected. Which of the following mode of inheritance do you suggest for this disease?
Autosomal dominant
Sex-linked dominant
Sex-limited recessive
Sex-linked recessive
D.
Sex-linked recessive
Sex linked characteristic is determined by the genes located on the sex chromosome ie X or Y. Sex limited characteristic is the condition where expression of sex linked genes is limited to one sex.
In the given problem, neither man nor woman are deceased by the disease. Therefore, women must be the carrier of the disease causing gene. Also, none of the daughters are suffereing from the disease except the sons, ie, daughters are also carrier.
Suppose, XY = genotype of man
XdX = genotype of woman (d refers to disease causing gene)
The probability for each combination is 25%. Therefore, among seven children, 2 are normal daughter, 3 diseased sons and 2 normal sons are possible.
Using imprints from a plate with complete medium and carrying bacterial colonies, you can select streptomycin resistant mutants and prove that such mutations do not originate as adaptation. These imprints need to be used
only on plates with streptomycin
on plates with minimal medium
only on plates without streptomycin
on plates with and without streptomycin
In order to find out the different types of gametes produced by a pea plant having the genotype AaBb, it should be crossed to a plant with the genotype
aaBB
AaBb
AABB
aabb
Which of the following is not a hereditary disease?
Cretinism
Cystic fibrosis
Thalassaemia
Haemophilia
A woman with 47 chromosomes due to three copies of chromosome 21 is characterized by
Down syndrome
triploidy
Turner syndrome
super femaleness
de Vries gave his mutation theory on organic evolution while working on
Althea rosea
Drosophila melanogaster
Oenothera lamarckiana
Pisum sativum
Kappa particles indicate
nuclear inheritance
cytoplasmic inheritance
mutation
nucleo-cytoplasmic inheritance
A haemophilic woman marries a normal man then
all the children will be normal
all the sons will be haemophilic
all the girls will be haemophilic
half girls will be haemophilic
Husband has blood group A and wife has blood group B. What is the blood group of children
A
B
AB
A, B, AB or 0
A woman with normal vision, but whose father was colourblind, marries a colourblind man. Suppose that the fourth child of this couple was a boy. This boy
must have normal colour vision
will be partially colourblind since he is heterozygous for the colourblind mutant allele
must be colourblind
may be colourblind or may be of normal vision
