Advertisements
Advertisements
प्रश्न
Explain the phenomena of dominance, multiple allelism and co-dominance taking human ABO blood group as an example.
उत्तर
The inheritance of ABO blood groups in humans exhibits dominance, codominance, and multiple allelism. In humans, the ABO blood groups are controlled by a gene called gene ‘I’. It has three alleles, namely IA, IB and i.
Dominance: The alles IA and IB are dominant over the allele i. IA and IB produce antigens A and B respectively, however allele i does not produce any antigen.
Co-dominance: If both IA and IB are present in an individual, then they both are expressed because of the phenomenon of co-dominance.
Multiple allelism: Since the blood grouping is governed by more than two alleles, it is a good example of multiple allelism.
Table Showing the Genetic Basis of Blood Groups in Human Population is given as follows:
|
Allele from Parent 1 |
Allele from Parent 2 |
Genotype of offspring |
Blood-types of offspring |
|
IA |
IA |
IA IA |
A |
|
IA |
IB |
IA IB |
AB |
|
IA |
i |
IAi |
A |
|
IB |
IA |
IA IB |
AB |
|
IB |
IB |
IB IB |
B |
|
IB |
i |
IBi |
B |
|
i |
i |
i i |
O |
APPEARS IN
संबंधित प्रश्न
Two independent monohybrid crosses were carried out involving a tall pea plant with a dwarf pea plant. In the first cross, the offspring population has equal number of tall and dwarf plants, whereas in the second cross it was different. Work out the crosses and explain giving reasons for the difference in the offspring population.
How does the gene 'I' control ABO blood groups in humans ? Write the effect the gene has on the structure of red blood cells.
Explain the genetic basis of blood grouping in human population.
In Snapdragon, a cross between true-breeding red flowered (RR) plants and truebreeding white flowered (rr) plants showed a progeny of plants with all pink flowers.
What is this phenomenon known as?
Name the stage of cell division where segregation of an independent pair of chromosomes occurs.
If the mother is a carrier of colour blindness and the father is normal, the possible genotype and
the phenotype of the offspring of the next generation, with the help of a punnet square
Given below is the representation of a relevant part of the amino acid composition of the β-chain of hemoglobin, related to the shape of human red blood cells.
(a) Is this representation of the sequence of amino acids indicating a normal human or a sufferer from certain blood related genetic diseases? Give reasons in support of your answer.
(b) Why is the disease referred to as a Mendelian disorder? Explain.
When a single gene influences more than one traits it is called ______.
What does low hematocrit value represent?
The normal pH of blood is ______.
