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1. Introduction to Genetics51m
2. Mendel's Laws of Inheritance3h 37m
3. Extensions to Mendelian Inheritance2h 41m
4. Genetic Mapping and Linkage2h 28m
5. Genetics of Bacteria and Viruses1h 21m
6. Chromosomal Variation1h 48m
7. DNA and Chromosome Structure56m
8. DNA Replication1h 10m
9. Mitosis and Meiosis1h 34m
10. Transcription1h 0m
11. Translation58m
12. Gene Regulation in Prokaryotes1h 19m
13. Gene Regulation in Eukaryotes44m
14. Genetic Control of Development44m
15. Genomes and Genomics1h 50m
16. Transposable Elements47m
17. Mutation, Repair, and Recombination1h 6m
18. Molecular Genetic Tools19m
- Genetic Cloning
  9m
- Methods for Analyzing DNA
  9m
19. Cancer Genetics29m
- Overview of Cancer
  21m
- Cancer Mutations
  7m
20. Quantitative Genetics1h 26m
21. Population Genetics50m
- Hardy Weinberg
  19m
- Allelic Frequency Changes
  31m
22. Evolutionary Genetics29m

3. Extensions to Mendelian Inheritance

X-Inactivation

Genetics

3. Extensions to Mendelian Inheritance

X-Inactivation

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Multiple Choice

Which of the following events results in X-inactivation in female mammals?

Activation of SRY gene on the X chromosome

Random loss of one X chromosome in each cell

Duplication of the X chromosome during mitosis

Expression of the XIST gene on one X chromosome

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Verified step by step guidance

Understand that X-inactivation is a process in female mammals where one of the two X chromosomes in each cell is silenced to balance gene dosage between males (XY) and females (XX).

Recognize that the SRY gene is located on the Y chromosome, not the X chromosome, so activation of SRY does not cause X-inactivation.

Know that random loss of one X chromosome or duplication of the X chromosome during mitosis are not mechanisms that lead to X-inactivation; these are different cellular events.

Focus on the role of the XIST gene, which is expressed from the X chromosome that will be inactivated; XIST RNA coats that X chromosome and triggers its silencing.

Conclude that the expression of the XIST gene on one X chromosome initiates the X-inactivation process, making it the correct event responsible for X-inactivation in female mammals.