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Question
Explain the inheritance of sex-linked characters in human being.
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Solution
Haemophilia is commonly known as bleeder’s disease, which is more common in men than women. This hereditary disease was first reported by John Cotto in 1803. Haemophilia is caused by a recessive X-linked gene. A person with a recessive gene for haemophilia lacks a normal clotting substance (thromboplastin) in blood, hence minor injuries cause continuous bleeding, leading to death. The females are carriers of the disease and would transmit the disease to 50% of their sons even if the male parent is normal. Haemophilia follows the characteristic criss - cross pattern of inheritaitce.
RELATED QUESTIONS
Match the terms in column I with their explanations in column II.
| Column I (Term) | Column I (Explanation) | ||
| a | genetics | 1 | Chromosomes similar in size and shape |
| b | Autosomes | 2 | The alternative forms of a gene |
| c | Recessive gene | 3 | Study of laws of inheritance of characters |
| d | Allele | 4 | A gene that can express only when in a similar pair |
| e | Homologous chromosomes | 5 | Chromosomes other than the pair of sex chromosomes |
A family consists of two parents and their five children and the pedigree chart shown below shows the inheritance of the trait colour blindness in them.
How many daughters and how many sons have been born in the family?
A family consists of two parents and their five children and the pedigree chart shown below shows the inheritance of the trait colour blindness in them.
What does the child 1 indicate about this trait?
A woman had normal vision, but her father was colourblind. She marries a man, who is colourblind.
Find out the probability of the first child being colourblind, whether it is a boy or girl.
A haemophilic man marries a carrier women. Find out the probability of their offsprings being haemophilic.
A family has five daughters and expecting sixth child. The chance of its beings a son is
The criss-cross pattern of inheritance is observed in ____________.
The genes present on non-homologous part of Y-chromosome are called ____________.
Name any two X-Linked recessive disorders.
Given diagram is a simplified representation of human sex chromosome. The gene A and B could be of ______.
