Results 21 to 30 of about 7,415,942 (348)
Reproduction, 1968 The slight excess of male births in most mammals reflects the interplay of two factors, the primary sex ratio at fertilization and the possible existence of a sex difference in pre-natal mortality. Among the explanations of this putative departure of the primary sex ratio from unity is that spermatozoa bearing the smaller Y-chromosome are more motile ...
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Climate influences fledgling sex ratio and sex-specific dispersal in a seabird. [PDF]
PLoS ONE, 2013 Climate influences the dynamics of natural populations by direct effects over habitat quality but also modulating the phenotypic responses of organisms' life-history traits. These responses may be different in males and females, particularly in dimorphic
Alvaro Barros +2 more
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Sex ratio elasticity influences the selection of sex ratio strategy [PDF]
Scientific Reports, 2016 There are three sex ratio strategies (SRS) in nature—male-biased sex ratio, female-biased sex ratio and, equal sex ratio depending on the proportion of male offspring being greater than, less than, or equal to ½. The problem was already noted in Darwin’s (1859) “Origin of Species,” and it was R. A.
Wang, Yaqiang +3 more
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EVALUATION OF SEMEN SEX RATIO IN COOLED AND FROZEN SEMEN STRAWS BY REAL-TIME PCR [PDF]
Basrah Journal of Veterinary Research, 2016 The study was demonstrated on quantitative evaluation of SRY and ZFX gene of (120) semenstraws from 10 Holliston bull (60) straws in cooling state 5C° and 60 straws after deep freezingin liquid nitrogen) .
Baqer Ja’fer. Hassan +2 more
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Natural and Engineered Sex Ratio Distortion in Insects
Frontiers in Ecology and Evolution, 2022 Insects have evolved highly diverse genetic sex-determination mechanisms and a relatively balanced male to female sex ratio is generally expected. However, selection may shift the optimal sex ratio while meiotic drive and endosymbiont manipulation can ...
Austin Compton +3 more
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Demographic causes of adult sex ratio variation and their consequences for parental cooperation
Nature Communications, 2017 The adult sex ratio (ASR) is a fundamental concept in population biology, sexual selection, and social evolution. However, it remains unclear which demographic processes generate ASR variation and how biases in ASR in turn affect social behaviour.
Luke J. Eberhart-Phillips +13 more
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A CRISPR-Cas9 sex-ratio distortion system for genetic control
Scientific Reports, 2016 Genetic control aims to reduce the ability of insect pest populations to cause harm via the release of modified insects. One strategy is to bias the reproductive sex ratio towards males so that a population decreases in size or is eliminated altogether ...
R. Galizi +9 more
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Modeling and forecasting sex differences in mortality: a sex-ratio approach
Genus, 2018 Female and male life expectancies have converged in most industrialized societies in recent decades. To achieve coherent forecasts between females and males, this convergence needs to be considered when forecasting sex-specific mortality.
Marie-Pier Bergeron-Boucher +3 more
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Haploid selection, sex ratio bias, and transitions between sex-determining systems.
PLoS Biology, 2018 Sex determination is remarkably dynamic; many taxa display shifts in the location of sex-determining loci or the evolution of entirely new sex-determining systems. Predominant theories for why we observe such transitions generally conclude that novel sex-
Michael Francis Scott +2 more
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Mother's occupation and sex ratio at birth
BMC Public Health, 2010 Background Many women are working outside of the home, occupying a multitude of jobs with varying degrees of responsibilities and levels of psychological stress. We investigated whether different job types in women are associated with child sex at birth,
Amiot Volodymyr +3 more
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