نتایج جستجو برای: sex dimorphism
تعداد نتایج: 211443 فیلتر نتایج به سال:
Sexual dimorphism is an interesting biological phenomenon. Previous studies showed that DNA methylation might play a role in sexual dimorphism. However, the overall picture of the genome-wide methylation landscape in sexually dimorphic species remains unclear. We analyzed the DNA methylation landscape and transcriptome in hybrid tilapia (Oreochromis spp.) using whole genome bisulfite sequencing...
In bovine preimplantation development, female embryos progress at lower rates and originate smaller blastocysts than male counterparts. Although sex-specific gene expression patterns are reported, when and how sex dimorphism is established is not clear. Differences among female and male early development can be useful for human assisted reproductive medicine, when X-linked disorders risk is det...
Mechanisms underlying sex differences in cancer incidence are not defined but likely involve dimorphism (s) in tumor suppressor function at the cellular and organismal levels. As an example, sexual dimorphism in retinoblastoma protein (Rb) activity was shown to block transformation of female, but not male, murine astrocytes in which neurofibromin and p53 function was abrogated (GBM astrocytes)....
Behavioural variation among conspecifics is typically contingent on individual state or environmental conditions. Sex-specific genetic polymorphisms are enigmatic because they lack conditionality, and genes causing adaptive trait variation in one sex may reduce Darwinian fitness in the other. One way to avoid such genetic antagonism is to control sex-specific traits by inheritance via sex chrom...
Alternative reproductive tactics (ARTs) are part of a much larger class of alternative phenotypes that include sex allocation and alternative life histories. We examine the evolution of ARTs by drawing on the much larger base of theory from sex-allocation and life-history evolution. Insights into how alternative tactics evolve (their maintenance in populations, the evolution of their underlying...
In many animal species, males and females attain different adult body sizes. The processes underlying such sexual differences are undoubtedly complex and may involve an interplay between adaptive, exaptive, and nonadaptive genetic influences on the one hand and environmental variables on the other. For example, large body size may be shown by males because genes for that character confer a sele...
Sexual size dimorphism is widespread throughout seabird taxa and several drivers leading to its evolution have been hypothesised. While the Australasian Gannet (Morus serrator) has previously been considered nominally monomorphic, recent studies have documented sexual segregation in diet and foraging areas, traits often associated with size dimorphism. The present study investigated the sex dif...
Sex differences in spatial learning have been reported in both humans and rodents. Correspondingly, there have been reports of sexual dimorphism in the morphology of the hippocampal formation (HF), a brain structure implicated in spatial cognition. In Experiment 1, we confirmed earlier reports that the overall volume of the granule cell layer (GCL) of the dentate gyrus (DG) of A/J mice is large...
This paper presents the results of a comprehensive study of sexual dimorphism in the human occipital region of the skull using the remains of 39 prehistoric adults from the prehistoric Windover (6,000-8,000 BP). The results of a discriminant analysis classified 64% of the individuals correctly (using osteologically identified sex). Sexual dimorphism in this population may not be prevalent due t...
Most animals have separate sexes. The differential expression of gene products, in particular that of gene regulators, is underlying sexual dimorphism. Analyses of sex-biased expression have focused mostly on protein-coding genes. Several lines of evidence indicate that microRNAs, a class of major gene regulators, are likely to have a significant role in sexual dimorphism. This role has not bee...
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