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.
What is the inheritance pattern observed in the size of starch grains and seed shape of Pisum sativum? Workout the monohybrid cross showing the above traits. How does this pattern of inheritance deviate from that of Mendelian law of dominance?
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
Explain Pleiotropy with reference to phenylketonuria.
When a single gene influences more than one traits it is called ______.
In human beings, where genotype AABBCC represents dark skin colour, aabbcc represents light skin colour and AaBbCc represents intermediate skin colour; the pattern of genetic inheritance can be termed as: ______
Genotypic ratio of 1:2:1 is obtained in a cross between ______
Four triplet codons code for the amino acid valine. Three of them are given below.
GUU GUC GUA
Write the fourth codon.
