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

4. Genetic Mapping and Linkage

Trihybrid Cross

Genetics

4. Genetic Mapping and Linkage

Trihybrid Cross

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Multiple Choice

The following table shows data from a cross examining three genes (a, b, and c). Determine the order of genes

A B C

B C A

C A B

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Examine the table to identify the parental genotypes and the number of offspring for each genotype. The parental genotypes are typically the ones with the highest number of offspring, which in this case are 'A B C' and 'a b c'.

Identify the double crossover genotypes, which are usually the ones with the lowest number of offspring. In this table, 'A B c' and 'a b C' have the lowest numbers, indicating double crossovers.

Determine the gene order by comparing the parental and double crossover genotypes. The gene that differs between the parental and double crossover genotypes is the middle gene. For example, if 'A B C' and 'a b c' are parental, and 'A B c' and 'a b C' are double crossovers, the gene that changes is 'B', suggesting 'B' is in the middle.

Use the single crossover genotypes to confirm the gene order. Single crossovers will have intermediate numbers of offspring and will show recombination between adjacent genes. Check the genotypes 'a B C', 'A b c', 'A b C', and 'a B c' to see which gene combinations are most frequent.

Conclude the gene order based on the analysis of parental, single crossover, and double crossover genotypes. The gene order is determined by the gene that changes in the double crossover and is confirmed by the single crossover patterns.

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Open Question

Domestic dogs evolved from ancestral gray wolves. Wolves have coats of short, straight hair and lack 'furnishings,' a growth pattern marked by eyebrows and a mustache found in some domestic dogs. In domestic dogs, coat variation is controlled by allelic variation in three genes. Recessive mutant alleles in the FGF5 gene result in long hair, while dogs carrying the dominant ancestral allele have short hair. Likewise, recessive mutant alleles in the KRT71 gene result in curly hair, whereas dogs with an ancestral dominant allele have straight hair. Dominant mutant alleles in the RSPO2 gene cause the presence of furnishings, while dogs homozygous for the ancestral recessive allele have no furnishings. A pure-breeding curly- and long-haired poodle with furnishings was crossed to a pure-breeding short- and straight-haired border collie lacking furnishings

If dogs of the F₁ generation are interbred, what proportions of genotypes and phenotypes are expected in the F₂?

Open Question

Domestic dogs evolved from ancestral gray wolves. Wolves have coats of short, straight hair and lack 'furnishings,' a growth pattern marked by eyebrows and a mustache found in some domestic dogs. In domestic dogs, coat variation is controlled by allelic variation in three genes. Recessive mutant alleles in the FGF5 gene result in long hair, while dogs carrying the dominant ancestral allele have short hair. Likewise, recessive mutant alleles in the KRT71 gene result in curly hair, whereas dogs with an ancestral dominant allele have straight hair. Dominant mutant alleles in the RSPO2 gene cause the presence of furnishings, while dogs homozygous for the ancestral recessive allele have no furnishings. A pure-breeding curly- and long-haired poodle with furnishings was crossed to a pure-breeding short- and straight-haired border collie lacking furnishings

What are the genotypes and phenotypes of the puppies?

Multiple Choice

The following table shows data from a cross (ABC x abc) examining three genes (a, b, and c). Calculate the recombination frequency for A and B

Multiple Choice

The following table shows data from a cross examining three genes (a, b, and c). Calculate the recombination frequency for A and C

Open Question

Determine whether the statements below are true or false. If a statement is false, provide the correct information or revise the statement to make it correct.The outcome of a trihybrid cross is predicted by the law of segregation.

Open Question

Determine whether the statements below are true or false. If a statement is false, provide the correct information or revise the statement to make it correct.

The progeny of a trihybrid cross are expected to have one of 27 different genotypes.

Open Question

Three gene pairs located on separate autosomes determine flower color and shape as well as plant height. The first pair exhibits incomplete dominance, where the color can be red, pink (the heterozygote), or white. The second pair leads to personate (dominant) or peloric (recessive) flower shape, while the third gene pair produces either the dominant tall trait or the recessive dwarf trait. Homozygous plants that are red, personate, and tall are crossed to those that are white, peloric, and dwarf. Determine the F₁ genotype(s) and phenotype(s). If the F₁ plants are interbred, what proportion of the offspring will exhibit the same phenotype as the F₁ plants?

Open Question

Researchers cross a corn plant that is pure-breeding for the dominant traits colored aleurone (C1), full kernel (Sh), and waxy endosperm (Wx) to a pure-breeding plant with the recessive traits colorless aleurone (c1), shrunken kernel (sh), and starchy (wx). The resulting F₁ plants were crossed to pure-breeding colorless, shrunken, starchy plants. Counting the kernels from about 30 ears of corn yields the following data.Kernel Phenotype NumberColored, shrunken, starchy 116Colored, full, waxy 601Colored, full, starchy 2538Colored, shrunken, waxy 4Colorless, shrunken, starchy 2708Colorless, full, starchy 2Colorless, full, waxy 113Colorless, shrunken, waxy 6266708What is the interference value for this data set?

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