Advertisements
Advertisements
प्रश्न
Jacob is genetically a carrier of the disorder that affects the shape of the RBCs, as shown in the diagram below. His son James suffers from the same disorder.
- Give the biochemical reason for the disorder that changes the shape of the RBCs, as shown above.
- Draw a Punnett square to show the genotype of the mother of James.
- Name and define the type of 'point mutation' responsible for this disorder.
उत्तर
- Red blood cells take on a sickle-like structure when oxygen tension is lowered since the deoxygenated sickle cell haemoglobin (HbS) molecules polymerize to form long fibres.
-
Given Jacob is a carrier, his genotype has to be HbA HbS.
James, Jacob's child, suffers with the condition; so, his genotype is HbS HbS.
According to the provided data, James must inherit one HbS allele from each parent if he is to have sickle call anaemia (HbS HbS). Given Jacob's known carrier status (HbAHbS), he most certainly passed on the HbS gene to James. James's need for two HbS alleles requires the mother to have likewise supplied a HbS allele. The condition (HbS HbS) or a carrier (HbA HbS) can have an impact on the mother.
Case 1. When mother is a carrier (HbA HbS)
Mother
HbA HbS HbA
JacobHbA HbA
(Normal)HbA HbS
(Carrier)HbS HbA HbS
[Carrier]HbS HbS
[Sickle cell]James will suffer from a disorder.
Case 2. When mother is affected (HbS HbS)
Mother
HbS HbS HbA
JacobHbA HbS
(Carrier)HbA HbS
(Carrier)HbS HbS HbS
[Sickle cell]HbS HbS
[Sickle cell]James will suffer from a disorder.
- A monogenetic condition, sickle cell anaemia is caused by a single base-pair point mutation in the β globin gene, substituting glutamic acid for valine in the β-globin chain.
APPEARS IN
संबंधित प्रश्न
Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross.
Give an example of a human disorder that is caused due to a single gene mutation.
Identify 'a', 'b', 'c',’d’, 'e' and 'f' in the table given below:
| No. | Syndrome | Cause | Characteristics of affected individuals | Sex Male/Female/Both |
| 1. | Down's | Trisomy of 21 | 'a' (i) (ii) |
'b' |
| 2. | 'c' | XXY | Overall masculine development. |
'd' |
| 3. | Turner's | 45 with XO | 'e' (i) (ii) |
'f' |
A male rabbit of genotype 'AABBDDEE' is crossed with a female rabbit of genotype 'aabbddee' to produce F1 hybrid offspring. How many genetically different gametes can be produced by this F1 hybrid?
Identify I and II in the given diagram of chromosome.
Match Column I with Column II and select the correct option:
| Column I | Column II | ||
| p. | Pleiotropy | I. | More than two alleles occur at the same locus on homologous chromosomes |
| q. | Multiple alleles | II. | Expression of both the alleles m heterozygous condition |
| r. | Polygenic | III. | Multiple effect of single gene |
| s. | Co-dominance | IV. | Single phenotypic character influenced by more than two genes |
Placed below is a karyotype of a human being.
On the basis of this karyotype, which of the following conclusions can be drawn: ______
Read the following and answer from given below:
Turner's syndrome is an example of monosomy. It is formed by the union of an allosome-free egg and a normal 'X' containing sperm or a normal egg and an allosome-free sperm. The individual has 2n = 45 chromosomes (44 + X0) instead of 46. Such individuals are sterile females who have rudimentary ovaries, underdeveloped breasts, small uterus, short stature, webbed neck, and abnormal intelligence. They may not menstruate or ovulate. This disorder can be treated by giving female sex hormones to women from the age of puberty to make them develop breasts and have menstruation. This makes them feel more normal.
Turner's syndrome is an example of ______
The technique exployed in human genetic counselling is:
Why is thalassemia cotegorised as a Mendelian disorder? Write the symptoms and explain the causes of the disease. How does it differ from Sickle cell anaemia?
