Q.What is gene mapping ?
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Start your 14-day free trial to unlock the full solution →Gene mapping locates genes on a chromosome in their relative linear order and distance apart, using crossing-over/recombination frequency as the measuring tool.
Genes located on the same chromosome are said to be linked, and the degree to which they are inherited together (rather than independently) depends on how close together they lie. Gene mapping (also called linkage/genetic mapping) is the technique used to work out the relative order of such linked genes along a chromosome and the distance between them.
The method relies on the phenomenon of crossing over, which occurs between homologous chromosomes during meiosis (prophase I) and results in recombinant gametes. The key principle is that:
- The frequency of recombination between two genes is roughly proportional to the physical distance separating them on the chromosome.
- Genes that lie CLOSE together show a LOW recombination frequency (they tend to stay together / show strong linkage).
- Genes that lie FAR apart show a HIGHER recombination frequency (approaching the 50% expected for independent assortment). …
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