Sec5b-LOD - LOD scores Bio137B J.L Marsh Where on the...

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LOD scores Bio137B J.L Marsh page 1 Where on the chromosome is a gene? RECOMBINATION MAPPING IN HUMANS I] The GENERAL PROBLEM 1] 2 point mapping in experimental organisms is simple cross AB/ab X ab/ab collect ~1000 progeny - compute RF by % recombinants 2] The role of Sample size & pooling of offspring - usually we pool offspring from several matings - BUT all matings start with parents of SAME genotype especially with respect to "PHASE"= coupling or repulsion or parental linkage. - When parents are all the same, all the progeny can be treated as if they arose from same parents 3] BUT We cannot pool data when "PHASE" is unknown. This is very typical in humans and to get enough progeny, we must pool data e.g. a b + + 10 map units a b + + 10 map units Repulsion Coupling + + + + Non recombinants Parentals 90% Recombinants 10% + Non recombinants Parentals 90% Recombinants 10% + + + POOLING GIVES 1:1:1:1 PATTERN OF SEGREGATION WHEN PHASE IS UNKNOWN b b b b a a a a
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Bio137B J.L Marsh page 2 There are two SOLUTIONS I] GRANDFATHER METHOD for X-LINKED TRAITS - PHASE in a given woman is revealed by her father's linkage - her children can be scored for recombination because their grandfather revealed the parental linkage Xg+ DMD Y Xg- DMD+ Xg- DMD+ linkage known Can score all her children for crossover OR just her sons if father's genotype renders daughters uninformative. Grandfather method of mapping X linked traits
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This note was uploaded on 10/27/2009 for the course BIO SCI 05580 taught by Professor Marsh during the Fall '09 term at UC Irvine.

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Sec5b-LOD - LOD scores Bio137B J.L Marsh Where on the...

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