Interval recombination between e and ro 2nd interval

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Unformatted text preview: rossovers between markers •  e.g. double crossover gives same result as no crossover •  e.g. triple crossover gives same result as one crossover, etc. •  two loci are considered linked if there is less than 50% recombina*on between them (generally less than 50 cM) –  “gene*c linkage” rela*onship between cM and physical distance (in nucleo*des) •  varies between species and between loca*ons in the genome –  some species have a lot of recombina*on, others do not –  some genomic regions have a lot of recombina*on, others do not •  in humans, 1 cM corresponds approximately to 1 million base pairs •  in the malaria pathogen Plasmodium falciparum, 1 cM corresponds to approximately 15,000 base pairs True, J.R., Mercer, J.M. and Laurie, C.C. 1996 Differences in crossover frequency and distribu*on among three sibling species of Drosophila. Gene.cs 142:507- 523. gene*c crosses are the basis of gene*c map construc*on •  genetic map = linkage map •  genetic map of D. melanogaster 52.0 - - - - - rosy (ry) three point cross •  e.g. D. melanogaster •  rosy (ry), ebony (e), rough (ro) –  all recessive crossing scheme P genera*on: ry e ro / ry e ro♀ X + + +/+ + + ♂ F1 genera*on: ry e ro/+ + + ♀ X ry e ro/ ry e ro ♂ score F2 phenotypes hkp://*cles/view/24694/figure/ 3 # RECOMBINATIONS RECOMB. INTERVAL - 0 - ry + + ------ry e ro 1 1ST + e ro ------ry e ro 1 1ST ry e + ------ry e ro RECOMBINANTS 0 +++ ------ry e ro PARENTALS ry e ro ------ry e ro 1 2ND + + ro ------ry e ro 1 2ND ry + ro ------ry e ro 2 1ST and 2ND +e+ ------ry e ro 2 1ST and 2ND # INDIVIDUALS # RECOMBINATIONS RECOMB. INTERVAL # INDIVI...
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This document was uploaded on 02/27/2014.

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