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Recombination Frequency and Gene Linkage Mapping

Recombination Frequency and Gene Linkage Mapping. Linked vs. Unlinked Genes. Crossing Over. Crossover Frequency. Mapping Using Frequency. Mapping Gene Loci. Recombination frequency. (Recombinant offspring) (Total offspring).

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Recombination Frequency and Gene Linkage Mapping

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  1. Recombination FrequencyandGene Linkage Mapping

  2. Linked vs. Unlinked Genes

  3. Crossing Over

  4. Crossover Frequency

  5. Mapping Using Frequency

  6. Mapping Gene Loci

  7. Recombination frequency (Recombinant offspring) (Total offspring)

  8. A wild-type fruit fly (heterozygous for gray body color and normal wings) was mated with a black fly with vestigial wings. The offspring has the following phenotypic distribution: Wild type (gray-normal) 778 Black-vestigial 785 Black-normal 158 Gray-vestigial 162 What is the recombination frequency between these genes for body color and wing type?

  9. A wild-type fruit fly (heterozygous for gray body color and normal wings) was mated with a black fly with vestigial wings. The offspring has the following phenotypic distribution: • Wild type 778 • Black-vestigial 785 • Black normal 158 • Gray vestigial 162 • What is the recombination frequency between these genes for body color and wing type? (158+162) / (778+785+158+162) 320/1873 0.171 = 17.1%

  10. In rabbits the dominant allele B produces a black coat color and the recessive genotype bb produces a brown coat. • Body fat color in rabbits is white if a dominant allele Y is present and yellow if the genotype is yy. • Assume the mating between rabbits with the following genotypes :Black with white fat – BBYYBrown with yellow fat - bbyy • produces the dihybrid - BbYy Black with white fat • Calculate the recombination frequency if the dihybrids are mated back to brown rabbits having yellow fat, bbyy, and the following ratio of phenotypes is observed: • BlackWhite125 • BlackYellow75 • BrownWhite85 • BrownYellow115

  11. In rabbits the dominant allele B produces a black coat color and the recessive genotype bb produces a brown coat. Body fat color in rabbits is white if a dominant allele Y is present and yellow if the genotype is yy. Assume the mating between rabbits with the following genotypes :Black with white fat - BBYYBrown with yellow fat - bbyy produces the dihybrid - BbYy Calculate the recombination frequency if the dihybrids are mated back to brown rabbits having yellow fat, bbyy, and the following ratio of phenotypes is observed: BlackWhite125 BlackYellow75 BrownWhite85 BrownYellow115 (75+85) / (125+115+75+85) 160/400 0.40 = 40%

  12. Question #1 • In rabbits, black (B) is dominant to brown (b), while full color (F) is dominant to chinchilla (f). The genes controlling these traits are linked. • The following cross was made: rabbits heterozygous for both traits that express black, full color, (BbFf) with rabbits that are brown, chinchilla (bbff). The following results were obtained: • 31 brown, chinchilla (bbff) • 35 black, full (B-F-) • 16 brown, full • 19 black, chinchilla • Determine the map distance between the 2 genes.

  13. Question #1 In rabbits, black (B) is dominant to brown (b), while full color (F) is dominant to chinchilla (f). The genes controlling these traits are linked. The following cross was made: rabbits heterozygous for both traits that express black, full color, with rabbits that are brown, chinchilla. The following results were obtained: 31 brown, chinchilla 35 black, full 16 brown, full 19 black, chinchilla Determine the map distance between the 2 genes (16+19) / (31+35+16+19) 35/101 0.35 = 35% 35 map units

  14. Determine the sequence of genes along a chromosome based on the following recombination frequencies: • b – vg 17 • cn-vg 8 • b-cn 9

  15. Determine the sequence of genes along a chromosome based on the following recombination frequencies: b – vg 17 cn-vg 8 b-cn 9

  16. Determine the sequence of genes along a chromosome based on the following recombination frequencies: b – vg 17 cn-vg 8 b-cn 9

  17. Determine the sequence of genes along a chromosome based on the following recombination frequencies: • A-B 8 • A-C 28 • A-D 25 • B-C 20 • B-D 33

  18. Determine the sequence of genes along a chromosome based on the following recombination frequencies: A-B 8 A-C 28 A-D 25 B-C 20 B-D 33

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