Chromosomal basis of inheritance - linkage crossing over, sex determination - Question Bank
1. A three-point cross is used to determine:
2. The phenomenon of X-chromosome inactivation in female mammals is an example of:
3. What is the Barr body?
4. In humans, the absence of the SRY gene on the Y chromosome leads to the development of:
5. The specific points on homologous chromosomes where crossing over occurs are called:
6. Which term describes genes located on the same chromosome that are inherited together?
7. The chromosomal theory of inheritance was independently proposed by:
8. Which of the following is an example of pleiotropy?
9. The phenomenon where a single gene controls multiple phenotypic traits is known as:
10. A fruit fly with XAAA (where X is one X chromosome and A represents a set of autosomes) would be:
11. In the fruit fly Drosophila, sex is determined by the X:autosome ratio. A fly with XXAA (where A represents a set of autosomes) would be:
12. Genes located in pseudoautosomal regions show inheritance patterns similar to:
13. Pseudoautosomal regions (PARs) are found on:
14. In species with XY sex determination, the X chromosome contains many more genes than the Y chromosome. These genes are called:
15. Interference (I) is related to the Coefficient of Coincidence (C.O.C.) by the formula:
16. Coefficient of coincidence (C.O.C.) is calculated as:
17. If interference is positive, it means that:
18. The phenomenon of 'interference' in crossing over refers to:
19. A test cross involving a heterozygous individual for two linked genes would reveal:
20. When crossing over occurs between two linked genes, what is the result?
21. Genes located on the Y chromosome are passed directly from:
22. Which of the following is a Y-linked trait in humans?
23. A male with a normal genotype for color vision (X^B Y) and a female carrier (X^B X^b) have children. What is the probability of their son being color blind?
24. Hemophilia is another well-known example of:
25. Color blindness is a classic example of which type of inheritance?
26. Why are X-linked recessive traits more common in males?
27. X-linked recessive traits are more commonly observed in which sex?
28. What is the term for genes located on the sex chromosomes?
29. In the ZW sex determination system, which sex has two different sex chromosomes?
30. In birds, sex determination is of the ZW type. Which sex is heterogametic?
31. The presence of the SRY gene on the Y chromosome is crucial for:
32. An individual with a karyotype of XO in humans is typically:
33. An individual with a karyotype of XXY in humans is typically:
34. Which chromosome is considered the male-determining chromosome in humans?
35. In humans, sex determination is primarily based on:
36. In Drosophila, sex is determined by:
37. Genes that are very far apart on the same chromosome behave as if they are:
38. What is the maximum recombination frequency observed between two linked genes?
39. If the recombination frequency between two genes is 10%, it means they are approximately how many map units apart?
40. A genetic map represents the relative positions of genes on a chromosome, with distances measured in:
41. Who developed the concept of gene mapping based on recombination frequencies?
42. The frequency of crossing over between two genes on the same chromosome is proportional to:
43. A chiasma (plural: chiasmata) is the visible manifestation of:
44. The physical exchange of genetic material between non-sister chromatids of homologous chromosomes is called:
45. Crossing over occurs during which stage of meiosis?
46. The phenomenon where alleles of different genes segregate independently during gamete formation is known as:
47. Linkage refers to the tendency of genes located on the same chromosome to:
48. Which organism did Thomas Hunt Morgan primarily use for his experiments on linkage and crossing over?
49. Who is credited with proposing the chromosomal theory of inheritance?