X larger than Y

Cui, Ke-Hui; Matthews, Colin D.

doi:10.1038/366117b0

Cited by 53 publications

(32 citation statements)

References 4 publications

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“…Kaneko et al [21] suggested that the sperm separation with Percoll gradients was due to differences in the basis of sperm velocity sedimentation, not on the basis of their buoyant density. The sperm sedimentation velocity may be influenced by differences in sperm head size or motility [15,22] but, there was no difference between the sperm head dimensions in the top and bottom fractions [22], but in contrast to a research report by Cui and Matthews [23].…”

Section: Discussioncontrasting

confidence: 49%

Assessment of Bovine X- and Y-bearing Spermatozoa in Fractions by Discontinuous Percoll Gradients with Rapid Fluorescence In Situ Hybridization

Kobayashi

Oguro

Uchida

et al. 2004

Journal of Reproduction and Development

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Abstract. This study was designed to apply the method of discontinuous Percoll gradients for sex preselection in bovine semen by using a current developed molecular technique, fluorescence in situ hybridization (FISH). In addition, we attempted to amplify the level of enrichment of X-or Y-bearing spermatozoa by treating for activating sperm motility performance with 10 mM caffeine. Bovine spermatozoa were fractionated on Percoll gradients into two major subpopulations of motile spermatozoa (bottom fraction) and weak motile spermatozoa (top fraction). The percentage of Ybearing spermatozoa in the top fraction (52.9%) slightly exceeded and that in the bottom fraction (44.3%) decreased significantly (P<0.001) compared with the theoretical ratio (50:50). Washing sperm with BO medium affected a deviation between the two sex populations, whereas semen activated with caffeine showed no difference in the percentage of X-and Y-bearing spermatozoa in both fractions compared with the theoretical ratio (50:50). These results show that the proportion of X-and Ybearing bovine spermatozoa can deviate after discontinuous Percoll gradients, although the proportion of X-and Y-bearing bovine spermatozoa was affected by sperm motility of the sample applied. Key words: Percoll separation, Semen sexing, FISH, Spermatozoa, Bovine (J. Reprod. Dev. 50: [463][464][465][466][467][468][469] 2004) ince the 1970s, several investigators have made a tt e m p t s t o s e p a r at e X -a n d Y -b e ar in g spermatozoa by means of various gradient techniques such as discontinuous albumin gradients [1, 2], Shepadex column s [2,3], discontinuous Percoll gradients [4,5] and the swim-up procedure [6]. None of these methods, however, have met with success sustainable and reproducible enough to achieve separation of Xand Y-bearing spermatozoa, and only flow cytometry has been proven to be effective [7]. One o f t h e p r o b l e m s a s s o c i a t e d w i t h r e s e a r c h attempting the separation of X-and Y-bearing spermatozoa has been the difficulty of validating the proportion of X-and Y-bearing spermatozoa within putatively separated sperm populations [8]. Early studies evaluated the efficiency of sperm separation by using quinacrine staining. Recent evidence has shown that the quinacrine method is unreliable and may not necessarily detect only the Y body at the Y chromosome in spermatozoa [9].Current development of DNA probes raised against the sex chromosome specific sequence gives

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Section: Discussioncontrasting

confidence: 49%

Assessment of Bovine X- and Y-bearing Spermatozoa in Fractions by Discontinuous Percoll Gradients with Rapid Fluorescence In Situ Hybridization

Kobayashi

Oguro

Uchida

et al. 2004

Journal of Reproduction and Development

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“…We would like to point out that the difference in the computed velocity between the X‐ and Y‐spermatozoa is due to their different dimensions, which results in a different DEP force as well as different drag force. Apart from the papers of Cui and Matthews as well as Cui , to the best of the authors’ knowledge, no other papers on the difference in size between the human X‐ and Y‐spermatozoa have been reported. The DEP force is a function of a number of other factors, which we had set to be incorporated within the constants D 0 and D 1 since there is yet to be any published article on the dielectric properties of human spermatozoa, keeping only the shape factor that is determined by the particle's geometry and dimension.…”

Section: Resultsmentioning

confidence: 99%

Dielectrophoresis of spermatozoa in viscoelastic medium

Koh

Marcos

2015

Electrophoresis

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Knowledge of spermatozoa motility is important in selecting suitable spermatozoa for assisted reproduction procedures. By considering the internal sliding force within an active filament, its shape in a viscoelastic Oldroyd-B fluid subjected to nonuniform electric field is presented. The resulting velocity is a function of the beating pattern and DEP force, which is dependent on the spermatozoon's morphology as well as the gradient of the mean square electric field. Finally, the velocities of the X- and Y-spermatozoa are compared under various conditions of nonuniform electric field and viscoelasticity of the medium. The presence of DEP force alters their velocities to different extents, giving an 84% level of confidence for selecting spermatozoon that contains the chromosome leading to a female. Therefore, a nonuniform electric field can be used not only to sort and select spermatozoa of desired morphology, but also for gender selection. Moreover, we found that sorting in a viscoelastic fluid medium is more effective as the effect of DEP on the spermatozoa velocity is enhanced by an order of magnitude.

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“…For this to be plausible, there would need to be some identifiable difference between the two types of spermatozoa. But apart from the minute difference in molecular weight (Cui and Matthews 1993), no differences have been found. Sperm morphology and motility have been studied extensively (see for example Davis et al 1992 andMoruzzi et al 1988) but nothing so far appears to give any indication of differences in vulnerability, motility or even ''progressiveness'' (for a full review see Baker and Bellis 1995).…”

Section: Competing Explanations: Damage To Y-spermmentioning

confidence: 55%

Paternal occupation and offspring sex ratio

Grant

Metcalf

2003

Sexualities, Evolution & Gender

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Between 1961 and 1997, there were 15 reports of unusual secondary sex ratios related to paternal occupation. Thirteen of these documented a statistically significant predominance of female births (low secondary sex ratios) to fathers working in specific occupations. Findings are summarized, as are authors' suggestions about possible causes for the observed phenomenon. In addition, a new study is reported, replicating the findings of low offspring sex ratios in the children of male anaesthetists. Discussion focuses on four possible explanations of the findings -sampling error, differential damage to sperm, the Trivers and Willard hypothesis (Trivers and Willard 1973), and the maternal dominance hypothesis (Grant

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X larger than Y

Cited by 53 publications

References 4 publications

Assessment of Bovine X- and Y-bearing Spermatozoa in Fractions by Discontinuous Percoll Gradients with Rapid Fluorescence In Situ Hybridization

Assessment of Bovine X- and Y-bearing Spermatozoa in Fractions by Discontinuous Percoll Gradients with Rapid Fluorescence In Situ Hybridization

Dielectrophoresis of spermatozoa in viscoelastic medium

Paternal occupation and offspring sex ratio

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