Table of contents

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

2. Mendel's Laws of Inheritance

Mendel's Experiments and Laws

Genetics

2. Mendel's Laws of Inheritance

Mendel's Experiments and Laws

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Multiple Choice

When completing fruit fly crosses to study Mendel's laws, which of the following best explains why the F2 generation often displays a phenotypic ratio of approximately 3:1?

Because environmental factors always override genetic inheritance in fruit flies

Because all offspring inherit only dominant alleles from both parents

Because alleles segregate independently during gamete formation, resulting in dominant and recessive phenotypes in a 3:1 ratio

Because the F2 generation is produced by self-fertilization of the P generation

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Verified step by step guidance

Understand that Mendel's laws describe how alleles (different forms of a gene) are inherited from parents to offspring, particularly focusing on the Law of Segregation.

Recall that during gamete formation (meiosis), alleles for a gene segregate so that each gamete carries only one allele for each gene.

Recognize that when two heterozygous individuals (F1 generation) are crossed, the alleles segregate independently, producing offspring with genotypes in a 1:2:1 ratio (homozygous dominant : heterozygous : homozygous recessive).

Translate these genotypic ratios into phenotypic ratios, where dominant alleles mask recessive ones, resulting in approximately 3 individuals showing the dominant phenotype for every 1 showing the recessive phenotype.

Conclude that the 3:1 phenotypic ratio in the F2 generation arises because of the segregation of alleles during gamete formation and the dominance relationship between alleles, not because of environmental factors or self-fertilization of the P generation.