The colour blindness is more likely to occur in males than in females because:
Correct answer: B. Genes responsible for certain traits, including colour blindness, are located on the X chromosome, which is part of the sex chromosomes
- A. The Y-chromosome of males has the genes for distinguishing colours
- B. Genes responsible for certain traits, including colour blindness, are located on the X chromosome, which is part of the sex chromosomes
- C. The trait is dominant in males and recessive in females
- D. None of the above
Explanation
Color blindness is caused by a recessive gene located on the X chromosome. Since males (XY) have only one X chromosome, any recessive gene on it will express itself, resulting in color blindness if present. Females (XX), however, have two X chromosomes, so a recessive gene on one can be masked by a dominant normal vision gene on the other X chromosome, making them carriers without expressing the trait. This genetic mechanism explains why color blindness is more prevalent in males. Option A is incorrect because the Y chromosome does not carry the genes for color vision. Option C is incorrect because the trait is not dominant in males; it is simply more likely to be expressed due to their single X chromosome. Option D is incorrect because option B accurately describes the situation.
Last updated
About Inheritance
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
Practise Inheritance
1,238 free Inheritance MCQs from Biology, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Exams that ask Biology questions like this
Biology is on 6 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
4 Mutations in opsin genes cause_ types of colorblindness.
9 : 3 : 3 : 1 ratio is given by:
A bald man marries to pattern bald woman. The chance of baldness in their daughter is:
A botanist sees that when he breeds a plant with blue flowers and a plant with red flowers, the resulting generation are plants with a 1:1 ratio of blue: red flowers. He knows that the two parents are homozygous for the trait of color. What phenomenon most likely explains the 1:1 ratio in the filial generation?
A carrier female for hemophilia can pass the defective allele to: