Sexual dimorphism is a term describing morphological differences between the sexes, but is often extended to include all differences observed between females and males. Sex differentiation in vertebrates is by definition sexually dimorphic and starts at the level of the sex chromosomes. In this review the sexual dimorphism of gonadal differentiation is discussed, with a focus on human developme...

the important of ostrich breeding have been increased in the iran as other country around the world. lack of sexual dimorphism in many species of birds including ostrich (struthio camelus), making it difficult to differentiate between males and females, especially in young birds. this can be problematic for breeding programs. blood samples from randomly chicks in the first days were collected a...

1. Parasites can affect host fitness, provoke host responses, and thereby mediate host life history evolution. As life history strategies are often sex-specific, immunological or behavioural responses of the host aiming to reduce the impact of parasites may be sexually dimorphic, e.g. as a consequence of sex differences in the resource allocation tradeoff between parasite defence, morphological...

Introduction: Anthropometric study is very important in the identification of sex especially when the body has been destroyed as a result of physical injury. The aim of this study, therefore, is to determine the presence of sexual dimorphism in the foramen magnum of skulls of North India region.. The sample comprised 96 skulls, of these skulls 50 are males and 46 females. The result obtained de...

Sexual dimorphism is a well-established phenomenon, but its degree varies tremendously among species. Since the early days of Einthoven's development of the three-lead galvanometer ECG, we have known there are marked differences in QT intervals of men and women. It required over a century to appreciate the profound implications of sex-based electrophysiological differences in QT interval on the...

Bill size is often viewed as a species-specific adaptation for feeding, but it sometimes varies between sexes, suggesting that sexual selection or intersexual competition may also be important. Hypotheses to explain sexual dimorphism in avian bill size include divergence in feeding niche or thermoregulatory demands, intrasexual selection based on increased competition among males, or female pre...

In pipefishes, males brood their offspring on their body or in a brood pouch. In 2 species of pipeflsh, Siphonostorna typhle and Nerophis ophidion, sexual dimorphism, dichromatism, and sex role reversal differed in degree between the species. N. ophidion females were larger than males, whereas in S. typhle sexes were equally large. Furthermore, N. ophidion females have pronounced sexual colouri...

Sex determination is an important step in biological identification from skeletal remains, especially in forensic circumstances. Many authors suggested that the morphological study was more subjective than the metric. There are various craniometric studies in different populations. They revealed that there was population-specific for the sex discriminant equation derived from each population. T...

Interventions that extend lifespan in mice can show substantial sexual dimorphism. Here, we show that male-specific lifespan extension with two pharmacological treatments, acarbose (ACA) and 17-α estradiol (17aE2), is associated, in males only, with increased insulin sensitivity and improved glucose tolerance. Females, which show either smaller (ACA) or no lifespan extension (17aE2), do not der...

results brdu ihc showed a significant decrease in neurogenesis following tld in both sexes showing more severity in male rats than in female rats. results of nissl staining and mwm also confirmed the brdu findings. regarding sexual dimorphism, our data showed no significant sex differences in the dg area of the hippocampus. conclusions sex-dependent reduction in neurogenesis following tld could...