Gene mapping – linkage maps, molecular markers, somatic cell hybrids - One Line Questions

1. A recombination frequency of 1% between two genes corresponds to a distance of: — 1 centimorgan
2. What is a 'marker' in the context of gene mapping? — A DNA sequence with a known location that can be identified.
3. What is a 'contig' in the context of physical mapping? — A set of overlapping DNA fragments that represent a continuous stretch of genomic DNA.
4. What is a Single Nucleotide Polymorphism (SNP)? — A variation in DNA sequence at a single nucleotide position.
5. SNP markers are useful because they are: — Abundant, highly polymorphic, and can be genotyped rapidly.
6. Which of the following statements about molecular markers is true? — Molecular markers detect variations in DNA sequences.
7. What is the term for a specific location on a chromosome where a gene or marker is found? — Locus
8. What is a 'diploid' organism in the context of genetics? — An organism with two complete sets of chromosomes.
9. What is the unit of genetic distance in a linkage map? —
10. How are genes assigned to specific chromosomes using somatic cell hybrids? — By analyzing the presence or absence of specific human enzymes (encoded by known genes) in hybrid cells that have lost specific human chromosomes.
11. In somatic cell hybridization, the loss of chromosomes from one species (e.g., human) is often a result of: — Preferential segregation during mitosis in the hybrid cell.
12. FISH is primarily used for: — Assigning genes to specific chromosomal bands or regions (physical mapping).
13. RFLP markers are based on variations in: — Restriction enzyme cutting sites.
14. Which of the following is a potential challenge when constructing a linkage map? — Ensuring markers are polymorphic and informative.
15. Somatic cell hybridization involves: — Fusion of somatic cells from different individuals or species.
16. Which of the following is NOT a direct output of linkage mapping? — Physical locations of genes on DNA
17. In human-rodent somatic cell hybrids, what is the typical outcome regarding chromosomes? — Human chromosomes are preferentially retained.
18. The phenomenon where genes on the same chromosome are inherited together more often than expected by chance is called: — Linkage
19. In linkage mapping, what phenomenon is used to determine the distance between genes? — Crossing over (recombination)
20. What is the main advantage of using somatic cell hybrids for gene mapping? — It can assign genes to entire chromosomes or large chromosomal segments.
21. What is the main challenge in constructing a high-resolution physical map of an entire genome? — The sheer size of the genome and the need to assemble large DNA fragments accurately.
22. Which technique directly measures the physical distance between DNA markers? — Fluorescence In Situ Hybridization (FISH)
23. Which type of map is generally considered more accurate for determining the precise location of genes? — Physical map
24. Which of the following statements about linkage maps and physical maps is FALSE? — Physical maps provide a more accurate representation of gene order than linkage maps.
25. During meiosis, homologous chromosomes can exchange segments. This process is known as: — Crossing over
26. Which method is commonly used to create high-density genetic maps with thousands of markers? — High-throughput sequencing and genotyping (e.g., SNP arrays, whole-genome sequencing).
27. What is the primary advantage of using molecular markers over phenotypic markers for gene mapping? — Molecular markers are not affected by environmental factors and can be identified throughout the life cycle.
28. Which type of map represents the linear arrangement of genes on a chromosome based on recombination frequencies? — Linkage map
29. Which molecular marker technique is often considered 'co-dominant' because it can distinguish between homozygous and heterozygous individuals? — RFLP
30. What is a limitation of using linkage mapping to map genes that are very close together? — Recombination events are too rare to be reliably detected.
31. What type of information does a physical map primarily provide? — The actual physical distance between genes on a chromosome.
32. A physical map represents gene locations based on: — Actual physical distances on the DNA molecule.
33. What is a limitation of RAPD markers? — Low reproducibility due to sensitivity to reaction conditions.
34. Which of the following is NOT a type of molecular marker used in gene mapping? — Mitochondrial DNA Sequencing (mtDNA)
35. Which type of marker is often generated by PCR using short, repeated DNA sequences as primers? — SSR
36. Which molecular marker technique utilizes PCR to amplify anonymous DNA fragments, with primer concentration being crucial? — RAPD
37. Which molecular marker technique involves digestion of DNA with restriction enzymes, ligation of adaptors, and selective amplification by PCR? — AFLP
38. Microsatellites (SSRs) are characterized by: — Variable numbers of short tandemly repeated DNA sequences.
39. The process of creating a linkage map typically involves analyzing the inheritance patterns of alleles in: — A population of related individuals (pedigree) or mapping populations (e.g., F2, recombinant inbred lines).
40. Which technique uses labeled DNA probes that hybridize to specific locations on chromosomes, often visualized under a microscope? — Fluorescence In Situ Hybridization (FISH)
41. What is a 'translocation' in the context of chromosomes? — The movement of a chromosome segment from one chromosome to a non-homologous chromosome.
42. The loss of specific human chromosomes from a somatic cell hybrid line, coupled with the retention of a specific human enzyme activity, suggests: — The gene for the enzyme is located on the retained chromosome.
43. What does a high recombination frequency between two genes suggest? — The genes are located far apart on the same chromosome or on different chromosomes.
44. What type of information does a linkage map primarily provide? — The order and relative distances between genes based on inheritance patterns.
45. What does it mean for two genes to be 'linked'? — They are located on the same chromosome and tend to be inherited together.
46. What is the primary advantage of SSR markers over RFLP markers? — They are generally more polymorphic and co-dominant.
47. What is the primary purpose of gene mapping? — To locate the relative positions of genes on chromosomes.
48. What is a key application of somatic cell hybridization in gene mapping? — To assign genes to specific chromosomes or chromosome regions.
49. What is a 'radiation hybrid' panel used for? — To generate cell lines with random fragments of one genome integrated into another, aiding in physical mapping.
All One Line Questions
E-Book Gene mapping – linkage maps, molecular markers, somatic cell hybrids Online Test Gene mapping – linkage maps, molecular markers, somatic cell hybrids Question Bank Gene mapping – linkage maps, molecular markers, somatic cell hybrids