Notes taken during lecture

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Published on 11 Feb 2011
School
UTSG
Department
Human Biology
Course
HMB265H1
LECTURE Feb. 10. 2011
Constructing a genetic map
Look at all different pairs of genes
Look at fraction of recombinants
Look at map distances
Thus know order and distances of genes
Use closest markers to give the most ACCURATE genetic maps
oSo double recombinant not hidden
Cross between two inbred lines
Calculate interference
Fewer crossover than expected under assumption of independence
Presumably due to some physical interference
oCrossover here makes crossover somewhere nearby more difficult
Rarest types are the double recombinants
Only one gene order makes these types the rarest
Most common types are parental if linked, double crossovers rarest
Single crossover intermediate
Determining gene order and distance corresponds well with physical distance
But not perfect correspondence
Centromere physical space but recombination suppressed here
oGenetic and physical distance doesnt correspond here well
Recombination mapping key in genetics, disease genetics, evolutionary, developmental
genetics…
Can locate gene that confers the particular phenotype without knowing the gene
beforehand
Segregation of genetically based phenotype and find where it is located in
proximity to other molecular markers and genes made possible by mapping
oLinkage mapping identifies location
Process of linkage mapping
Genomics
Align where particular disease is and find genetic space address, link it to
physical space address
What chromosome is the disease gene on? What is its location on the
chromosome?
Genetic linkage mapping key tool to all aspects of biology
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Document Summary

 use closest markers to give the most accurate genetic maps: so double recombinant not hidden. Fewer crossover than expected under assumption of independence.  presumably due to some physical interference: crossover here makes crossover somewhere nearby more difficult.  only one gene order makes these types the rarest. Most common types are parental if linked, double crossovers rarest. Determining gene order and distance corresponds well with physical distance.  centromere physical space but recombination suppressed here: genetic and physical distance doesn"t correspond here well. Recombination mapping key in genetics, disease genetics, evolutionary, developmental genetics .  can locate gene that confers the particular phenotype without knowing the gene beforehand.  segregation of genetically based phenotype and find where it is located in proximity to other molecular markers and genes made possible by mapping: linkage mapping identifies location.  align where particular disease is and find genetic space address, link it to physical space address.