Sex recombination, and reproductive fitness: an experimental study using Paramecium
The effect of sex and recombination on reproductive fitness are measured using five wild stocks of Paramecium primaurelia. Among the wild stocks there were highly significant differences in growth rates. No hybrid had as low a fitness as the least fit parental stock. Recombination produced genotypes of higher fitness than those of either parent only in the cross between the two stocks of lowest fitness. The increase in variance of fitness as a result of recombination was almost exclusively attributable to the generation lines with low fitness. The fitness consequences of sexuality and mate choice were stock specific; some individuals leaving the most descendants by inbreeding, others by outcrossing. For most crosses the short-term advantage of sex, if any, accrue from the fusion of different gametes (hybrid vigor) and not from recombination. Since the homozygous genotype with the highest fitnes left the most progeny by inbreeding (no recombination), the persistence of conjugation in P. primaurelia is paradoxical. (JMT)
- Research Organization:
- Argonne National Lab., IL
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 6377437
- Journal Information:
- Am. Nat.; (United States), Vol. 120:2
- Country of Publication:
- United States
- Language:
- English
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