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Question
About 8% of the human male population suffers from colour blindness, whereas only about 0.4% of the human female population suffers from this disease. Write an explanation to show how it is possible.
Solution
Colour blindness is a sex-linked disorder and is caused by a recessive gene located on the X chromosome. The Y chromosome of male does not carry any gene for colour vision and the defect appears in the presence of a single recessive gene (XcY). As a result, colour blindness is more common in males (8%) as compared to females (0.4%).
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RELATED QUESTIONS
If only one 'X' chromosome is found in a female person, which of the following symptoms she will show?
- epicanthal skin fold
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- small testis and absence of spermatogenesis
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Very Short Answer Question.
Give an example of a chromosomal disorder caused due to nondisjunction of autosomes.
Match the Column I and Column II and select the correct option.
| List-I | List-II | ||
| i. | Holandric genes | a. | Pleiotropy |
| ii. | Multiple effects of a single gene | b. | Hypertrichosis |
| iii. | Skin colour in man | c. | Multiple Alleles |
| iv. | ABO Blood types | d. | Polygenic inheritance |
The correct answer is
If a genetic disease is transferred from a phenotypically normal but carrier female to only some of the male progeny, the disease is ______.
Sickle cell anaemia is ______.
Where are the genes for cytoplasmic male sterility in plants located?
Failure of segregation of chromatids during cell division results in the gain or loss of chromosomes, this is called as ______.
Read the following and answer from given below:
According to Mendel, one gene controls the expression of one character only. The ability of a gene to have multiple phenotypic effects because it influences a number of characters are an exception. The gene has multiple phenotypic effects because its ability to control two or more characters can be seen in cotton. In cotton, a gene for the lint also influences the height of the plant, size of the ball, number of ovules, and viability of seeds.
Which of the following disorder is an example of genes with multiple phenotypic effects?
Give definition of non-disjunction.
What is the genotype of Turner's Syndrome?
