Chromosomal basis of inheritance - linkage crossing over, sex determination - One Line Questions

1. 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? — 25%
2. If the recombination frequency between two genes is 10%, it means they are approximately how many map units apart? — 10 map units
3. What is the maximum recombination frequency observed between two linked genes? — 50%
4. Which of the following is an example of pleiotropy? — Sickle cell anemia
5. What is the Barr body? — An inactivated X chromosome in female mammals
6. Color blindness is a classic example of which type of inheritance? — X-linked recessive
7. Hemophilia is another well-known example of: — X-linked recessive inheritance
8. What is the term for genes located on the sex chromosomes? — Sex-linked genes
9. Genes located in pseudoautosomal regions show inheritance patterns similar to: — Autosomal genes
10. Pseudoautosomal regions (PARs) are found on: — Both X and Y chromosomes
11. The specific points on homologous chromosomes where crossing over occurs are called: — Chiasmata
12. A chiasma (plural: chiasmata) is the visible manifestation of: — Crossing over events
13. The phenomenon where a single gene controls multiple phenotypic traits is known as: — Pleiotropy
14. Which organism did Thomas Hunt Morgan primarily use for his experiments on linkage and crossing over? — Drosophila melanogaster
15. The presence of the SRY gene on the Y chromosome is crucial for: — Male sex determination
16. Why are X-linked recessive traits more common in males? — Females have two X chromosomes to mask the recessive allele.
17. The phenomenon of X-chromosome inactivation in female mammals is an example of: — Dosage compensation
18. Who is credited with proposing the chromosomal theory of inheritance? — Sutton and Boveri
19. Interference (I) is related to the Coefficient of Coincidence (C.O.C.) by the formula: — I = 1 - C.O.C.
20. Which term describes genes located on the same chromosome that are inherited together? — Linkage
21. Crossing over occurs during which stage of meiosis? — Pachytene
22. The phenomenon where alleles of different genes segregate independently during gamete formation is known as: — Independent assortment
23. 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: — Female
24. A fruit fly with XAAA (where X is one X chromosome and A represents a set of autosomes) would be: — Male
25. In humans, the absence of the SRY gene on the Y chromosome leads to the development of: — Female characteristics
26. An individual with a karyotype of XXY in humans is typically: — Male with Klinefelter syndrome
27. An individual with a karyotype of XO in humans is typically: — Female with Turner syndrome
28. X-linked recessive traits are more commonly observed in which sex? — Males
29. In birds, sex determination is of the ZW type. Which sex is heterogametic? — Females (ZW)
30. A genetic map represents the relative positions of genes on a chromosome, with distances measured in: — Centimorgans (cM) or map units
31. The chromosomal theory of inheritance was independently proposed by: — Sutton and Boveri
32. Genes located on the Y chromosome are passed directly from: — Father to son
33. Coefficient of coincidence (C.O.C.) is calculated as: — Observed recombination frequency / Expected recombination frequency
34. When crossing over occurs between two linked genes, what is the result? — Both parental and recombinant gametes
35. Which of the following is a Y-linked trait in humans? — Hairy ears (Hypertrichosis)
36. Linkage refers to the tendency of genes located on the same chromosome to: — Be inherited together
37. Genes that are very far apart on the same chromosome behave as if they are: —
38. The physical exchange of genetic material between non-sister chromatids of homologous chromosomes is called: — Crossing over
39. A test cross involving a heterozygous individual for two linked genes would reveal: — All of the above
40. A three-point cross is used to determine: — The order and relative distances of three linked genes
41. In humans, sex determination is primarily based on: — The presence of a Y chromosome
42. The phenomenon of 'interference' in crossing over refers to: — The effect of one crossover event on the likelihood of another crossover nearby
43. If interference is positive, it means that: — The occurrence of one crossover decreases the chance of another nearby.
44. In Drosophila, sex is determined by: — The ratio of X chromosomes to autosomes
45. The frequency of crossing over between two genes on the same chromosome is proportional to: — Their physical distance
46. Who developed the concept of gene mapping based on recombination frequencies? — Alfred Sturtevant
47. Which chromosome is considered the male-determining chromosome in humans? — Y chromosome
48. In species with XY sex determination, the X chromosome contains many more genes than the Y chromosome. These genes are called: — X-linked genes
49. In the ZW sex determination system, which sex has two different sex chromosomes? — ZW (female)
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