Advertisements
Advertisements
Question
Explain the inheritance pattern of colour blindness with a suitable chart.
Advertisements
Solution
- A person suffering from colour blindness cannot differentiate between red and green colours. Both these colours appear grey to the colour blind person.
- It is caused due to recessive X-linked genes (Xc ) which prevent the formation of colour sensitive cells in the retina that are necessary for distinguishing red and green colours.
- Dominant X linked gene (XC ) is necessary for the formation of colour sensitive cells in the retina of the eye.
- The homozygous recessive females (Xc Xc ) and hemizygous recessive male (Xc Y) are unable to distinguish between red and green colours. The frequency of colour of blind women is much less than colour blind men.
- When a normal man marries a carrier woman, half of their sons may be colour blind, while the remaining half will have normal vision. All their daughters will have normal vision and half of them will be carriers for the disease.
- If a colour blind male (Xc Y) marries a female with normal vision (XC XC ), then all the offsprings will have normal vision. The sons will have normal vision but daughters will be carriers for the disease. The carriers have normal vision.
APPEARS IN
RELATED QUESTIONS
The three principles of Mendelism are
Write a note on bleeder’s disease and its inheritance with a suitable chart.
If two individuals with blood group 'AB' marry and have sufficiently large number of children, these children could be classified as 'A' blood group : 'AB' blood group: 'B' blood group in 1 : 2 : 1 ratio. Modem technique of protein electrophoresis reveals presence of both 'A' and 'B' type proteins in 'AB' blood group individuals. This is an example of ______.
The genotypes of a husband and wife are IAIB and IAi respectively. How many different genotypes and phenotypes are possible among the blood types of their children?
In cattle, when red one is crossed with a white, an intermediate roan coloured offspring is formed in the F1 generation. When selfing of the F1 generation was carried, the result obtained was ______
______ refers to a phenomenon in which heterozygotes have features of both the homozygotes, that is, an allele is neither dominant nor recessive to the other.
Define – Incomplete dominance.
Give a cross of co-dominance using a suitable example.
Fill in the blanks:
| Column 'A' (Gene interactions) |
Column 'B' (Example) |
|
| (1) | Co-dominance | ______ |
| (2) | Incomplete dominance | ______ |
| (3) | Multiple allelism | ______ |
| (4) | Pleiotropy | ______ |
| (5) | Polygenes | ______ |
| (6) | Autosomal dominance | ______ |
Which one of the following is an example of pleiotropy?
