Class 12th Biology 2018 Set1 Delhi Board Paper Solution
How did Sturtevant explain gene mapping while working with Morgan?
Gene linkage in a chromosome can be shown in the form of genetic map (linkage map or we can say chromosomal map). Alfred Sturtevant was the first individual who developed the genetic map. He used the recombination frequency of crossing over between two genes for the preparation of first genetic map of X chromosome of Drosophila. There are two aspects of genetic mapping: gene order, gene distance.
Crossing over occurs with increase in frequency as the distance increases between two specific gene loci. Recombinant frequency is used to define the measure of map distance between the two genes. The unit of measurement of genetic map is called as map unit or centimorgan (cM). 1 map unit or 1 cM is equal to 1% of recombination. Formula for map distance:
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