GENE MAPPING 2
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The document discusses gene linkage and mapping. It explains that Morgan found linked traits are located on the same chromosome, and chromosomes rather than genes independently assort during meiosis. Linked genes are not always inherited together due to chromosomes exchanging homologous genes during meiosis. Linkage maps estimate distances between genes based on crossover frequencies, with closer genes being inherited together more often.
GENE MAPPING 2
- 1. • GENE LINKAGE & MAPPING • By A.Arputha Selvaraj
- 2. KEY CONCEPT Genes can be mapped to specific locations on chromosomes.
- 3. Gene linkage was explained through fruit flies. • Morgan found that linked traits are on the same chromosome. • Chromosomes, not genes, assort independently during meiosis. Wild type Mutant
- 4. • Linked genes are not inherited together every time. • Chromosomes exchange homologous genes during meiosis.
- 5. Linkage maps estimate distances between genes. • The closer together two genes are, the more likely they will be inherited together. • Cross-over frequencies are related to distances between genes. – The higher the frequency, the further the genes are apart • Linkage maps show the relative locations of genes.
- 6. • Cross-over frequencies can be converted into map units. • Ex: A 5% cross-over frequency equals 5 map units. – gene A and gene B cross over 6.0 percent of the time – gene B and gene C cross over 12.5 percent of the time – gene A and gene C cross over 18.5 percent of the time
- 7. Draw a linkage map based on the following cross over percentages: • A – B = 8% • B – C = 10% • A – C = 2% 8.0 2.0 B A C 8.0 + 2.0 = 10.0
- 8. Thanks