Monday, 23 December 2013

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Genetic:Recombination map and Physical Map

1) Why are both recombination maps and physical maps important? What are the differences between them?
2) When does crossing over occur?
3) What kind of recombination frequency is diagnostic for linkage?
4) Why do we make test crosses for mapping with the double recessive line?
5) How do we measure ‘distance’ when we map?
Are distances relative or absolute?


1--recombination map is the linkage map it can only be constructed for loci that occur in two or more heritable forms

physical map can be made from direct DNA analysis both are important as we try to correlate for acurate test and result

2--Crossing over takes place at hotspot site where there is high degree of complementarity

3--If the genes were independent, using standard genetic techniques you would predict that your offspring would have the phenotypic ratio,this would help in linkage,

Linkage analysis can be used to diagnostics linkage

4--For detecting linkage we do double recessive lines

5--- linkage map unit (LMU) these are relative as it can vary with Frequency of crossover (and thus of recombination) can be affected by location (crossing over is repressed close to the centromere) and proximity to another corssover.

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