Chiasmata have no effect on fertility

Wallace, H.

doi:10.1038/hdy.1974.111

Cited by 11 publications

(6 citation statements)

References 10 publications

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“…Cohen (1973) maintains that there is a positive correlation between sperm redundancy (the number of sperm ejaculated to fertilise a single egg) and chiasma count, covering a great diversity of species with totally different reproductive physiology. Within related species, Wallace (1974) could not find such a relation.…”

Section: Tablementioning

confidence: 79%

Son-sire regression based heritability estimates of chiasma frequency, using T70H mouse translocation heterozygotes, and the relation between univalence, chiasma frequency and sperm production

Boer

Hoeven

1977

Heredity

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SUMMARYT( 1; 13) 7011/ + translocation heretozygous mice were used for assessing heritability values for chiasma frequencies and the epididymal sperm count. The chiasma frequency estimates were based on 15 son-sire pairs, the translocation hcterozygotes being maintained in a Swiss random-bred genetic background. The chiasma frequencies were scored separately for the T7OH/ + derived multivalent, specific pairing segments within the multivalent and the remaining bivalents. Chiasma counts within these specified parts of the genome were positively correlated. The heritability estimates, significantly greater than zero, ranged from 078-098, depending on the chromosome segments included. These results indicate a strong genetic control on a cellular basis for the formation of chiasmata in the mouse. Despite significantly positive correlations and regressions between the various chiasma frequencies and the sperm count (for which 29 pairs of observations were available), no significant heritability estimate for the sperm count was obtained. The relation between the chiasma frequency and the sperm count was weakest when the chiasma count was confined to a region of the translocation-caused multivalent in which the absence of a chiasma almost always resulted in the production of an univalent. This indicates that in the translocation heterozygotes used, the overall chiasma frequency has a greater predictive value for the sperm count than autosomal univalence alone.

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Section: Tablementioning

confidence: 79%

Son-sire regression based heritability estimates of chiasma frequency, using T70H mouse translocation heterozygotes, and the relation between univalence, chiasma frequency and sperm production

Boer

Hoeven

1977

Heredity

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“…Cohen (1973,1975) suggested that spermatozoa may be of two kinds, only one of which is normally permitted to reach the fertilization site at the time of fertilization, by selection in the female tract. He has been misquoted (Wallace, 1974;Gwatkin, 1977) as asserting that only a small proportion of spermatozoa can fertilize; the problem of whether each spermatozoon can fertilize if it gets to an egg remains to be solved.…”

Section: Introductionmentioning

confidence: 99%

In-vitro fertilization in the mouse and the relevance of different sperm/egg concentrations and volumes

Siddiquey¹,

Cohen²

1982

Reproduction

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The sperm:egg ration and sperm concentration were varied separately by using different volumes (1--100 microliters) and egg numbers (1--15). The % fertilization was determined by sperm concentration in large volumes (10--100 microliters). In small volumes (1 or 5 microliters) the number of spermatozoa/egg determined penetration rate: the effective epididymal sperm number/fertilization was 250--350. Spermatozoa obtained from the oviducts (i.e. naturally selected) gave good fertilization responses and low concentrations of epididymal spermatozoa were also more effective when oviducal fluid and cumulus cells were included in the inseminating volume. We conclude that sperm/egg collision rate is the most important factor determining % fertilization, although heterogeneity of epididymal spermatozoa limits fertilization rate at low sperm:egg ratios.

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“…Good evidence exists that they so act in several rodent spe-cies (Martan and Shepherd, 1976;Hartung and Dewsbury, 1978;Milligan, 1979;Murie and McLean, 1980;Michener, 1984), but several exceptions exist (Hartung and Dewsbury, 1978;Oglesby et al, 1981;Dewsbury, 1988). Cohen's (1973) hypothesis that deformed sperm arise from uncorrected mistakes of meiosis in a diploid organism has been questioned before (Wallace, 1974;Bedford et al, 1984), but Baker and Bellis's is the first suggestion that the deformities are adaptive. I here discuss their "kamikaze" sperm hypothesis in detail, taking into account their modifications of the hypothesis (Baker and Bellis, 1989) in the light of a previous brief criticism of it (Harcourt, 1989).…”

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confidence: 99%

Sperm Competition and the Evolution of Nonfertilizing Sperm in Mammals

Harcourt¹

1991

Evolution

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Nonfertilizing sperm with special morphologies have long been known to exist in invertebrates. Until recently, abnormal sperm in mammals were considered errors in production. Now, however, Baker and Bellis (1988, 1989) have proposed that mammalian sperm, like some invertebrate sperm, are polymorphic and adapted to a variety of nonfertilizing roles in sperm competition, including prevention of passage of sperm inseminated by another male. More specifically, their "kamikaze" sperm hypothesis proposes that deformed mammalian sperm are adapted to facilitate the formation and functioning of copulatory plugs (Baker and Bellis, 1988). Here I argue that most, maybe all, mammals are unlikely to produce nonfertilizing sperm. First, mammals might not be able to afford to evolve nonfertilizing sperm, given that a) fertilization is often unlikely despite the huge numbers of sperm produced; b) production of larger numbers of sperm is constrained, presumably because of metabolic costs, evidence for which includes the fact that in species in which sperm morphology and anatomy of the female reproductive tract increase the probability of fertilization, the numbers of sperm produced is lower than in others; and c) selection appears to act against the production of deformed sperm. Second, some of the evidence advanced for the existence of nonfertilizing sperm does not in fact support the idea. Third, accessory gland secretions are sufficient on their own to coagulate semen and produce fully functioning plugs; thus the male that used accessory gland secretions would be at a clear advantage over the male that diluted his fertilizing sperm with "kamikaze" sperm; and indeed, current evidence indicates selection on accessory glands, not sperm morphology, to enhance coagulation of semen. Fourth, predictions made on the basis of the "kamikaze" sperm hypothesis are not supported by quantitative comparisons of data from polyandrous and monandrous primates (i.e., those in which several males mate with a fertile female, and therefore in which sperm competition should be operating, and those in which only one male mates). Although sperm competition is almost certainly more intense in polyandrous genera than in monandrous genera (as indicated by, e.g., more frequent copulations and the production of more sperm per ejaculate from larger spermatogenic organs), polyandrous genera do not produce a greater proportion of deformed (i.e., nonfertilizing) sperm than do monandrous genera, or even necessarily a greater number of deformed sperm; nor a greater variety of sperm sizes-indeed they might produce fewer; nor fewer motile sperm (as might be expected if sperm are selected to stay behind and compete with sperm from subsequent males); and nor larger sperm (as might be expected if sperm are produced for functions other than to reach the egg). In sum, currently available evidence suggests that the function of all mammalian sperm is to fertilize, and that sperm competition in mammals occurs through scramble competition, not contest competition.

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Chiasmata have no effect on fertility

Cited by 11 publications

References 10 publications

Son-sire regression based heritability estimates of chiasma frequency, using T70H mouse translocation heterozygotes, and the relation between univalence, chiasma frequency and sperm production

Son-sire regression based heritability estimates of chiasma frequency, using T70H mouse translocation heterozygotes, and the relation between univalence, chiasma frequency and sperm production

In-vitro fertilization in the mouse and the relevance of different sperm/egg concentrations and volumes

Sperm Competition and the Evolution of Nonfertilizing Sperm in Mammals

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