In humans XXY individual produced through non-disjunction is sterile male. However, in Drosophila (fruit-flies), XXY set of chromosomes produces a fertile female.This happens because sex determination in Drosophila depends on the number of:
Correct answer: A. X chromosomes relative to the number of autosomes
- A. X chromosomes relative to the number of autosomes
- B. Y chromosomes relative to the number of autosomes
- C. Autosomes relative to the number of XY chromosomes
- D. Y chromosomes relative to the number of X chromosomes.
Explanation
In Drosophila, sex determination is based on the ratio of X chromosomes to sets of autosomes (A), rather than the presence of a Y chromosome, which is crucial in humans. A ratio of 1.0 (for instance, XX:2A) results in a female, while a ratio of 0.5 (for instance, XY:2A) results in a male. Thus, an XXY individual in Drosophila, with a ratio of 1.0, develops as a fertile female. This is different from humans, where the presence of a Y chromosome typically leads to male characteristics. Therefore, the correct answer is related to the number of X chromosomes relative to autosomes, not Y chromosomes.
Last updated
About X-linked Recessive Inheritance
X-linked recessive inheritance involves genes on the X chromosome, so males express a recessive allele with no corresponding allele on their single X chromosome, while females may be carriers. Pedigrees cover haemophilia and red-green colour blindness, including carrier mothers, affected sons and the absence of father-to-son transmission.
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
A baby girl is born with hemophilia, which is an X-linked recessive disorder. What are the most likely genotypes of her parents?
A carrier of an X-linked recessive disorder is
A colour blind girl can be born only if
A condition that renders the individual less able to form blood clots is:
A man has hemophilia. Which statement correctly describes the inheritance of this gene?