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Biology - Calculating map distance of genes

Calculating map distance of genes

* Linked genes are those on the same chromosome [1] but at different loci

* The closer together genes are on the same chromosome the less likely
crossing over will occur

* The further apart the loci of the genes are the more likely crossing
over [2] will occur

* A crossing over frequency of 1% represents a distance of 1 map unit

* Parents of known genotypes [3] are crossed to determine the number of
parental and recombinant phenotypes [4] in the offspring.

If the cross over frequency between genes D and G is 32% then genes D and
G are 32 map units apart on the chromosome.

Through deliberate matings or trial and error, a map of a chromosome can
be built up. In 1999, one human chromosome was mapped completely, though
not by deliberate matings or trial and error!

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Links:
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[1] http://alison.com/#
[2] http://alison.com/#
[3] http://alison.com/#
[4] http://alison.com/#