Blackwell Publishing

Multi-locus population genetics - Why does recombination exist?


One possible explanation for recombination can be ruled out:

Natural selection can only work on something if it is genetically variable. If there were no genetic variation in recombination rates, it could not be reduced to zero.

However, as the figure shows, experiments have selected successfully for both higher and lower recombination rates in fruitflies.

Recombination can also be reduced by the establishment of a chromosomal inversion. Research by Dobzhansky has emphasized that chromosomal inversions protect sets of epistatically interacting genes.

These two factors show that the rate of recombination can be lowered and it is unlikely that recombination persists only because natural selection cannot eliminate it.

Figure: artificial selection can increase or decrease the rate of recombination. These results are for the rate of recombination between two loci in lab stocks of Drosophila. From Kidwell (1972).

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