Female-led infanticide in wild chimpanzees
...r, but may stem from demographic shifts that alter sex ratios and put increased pressure on females compe...on changes resulted in a highly skewed male:female sex ratio of 1:3, with relatively few males available to increase the home range. According to the aut...Brains reflect sex differences
...o took into account the typical group size of each sex for individual primate species in order to assess sex-specific sociality - the tendency to associate with others and form social groups. The researchers then studied the differences between 21 primate species, which included chimpanzees, gorillas, an...Species thrive when sexual dimorphism broadens their niches
...reported this week in the journal Nature, suggests sex differences may have fueled the evolutionary flour...- but these radiations are studied in terms of one sex only, usually males. So we asked a simple question: If animals are adapting to their environment, bu...Research suggests men's sexual behavior adapts to perceived threats
...ith the idea of animals competing for mates before sex occurs, through mating displays such as bright fea...een the sexes, in which an advantage gained by one sex selects for counter-adaptations in the other sex."...Hearts of male and female rainbow trout are different
...de. There is a growing appreciation of significant sex differences in cardiac characteristics and functio... to close the gender gap in fishes, and finds that sex differences in cardiac performance and metabolism exist in rainbow trout. These differences occur at...Hot flashes -- Studies explore the role of genes, obesity and alcohol
...d lower total estradiol, estrone, progesterone and sex hormone binding globulin (SHBG) in midlife women. ..., the team thought that light drinking might alter sex steroid hormone levels in midlife women. But their analysis failed to turn up any significant hormon...Macaque genome analysis will help find human disease genes
...less variation on the X chromosome (one of the two sex chromosomes) than on others, Bustamente's group fo...t if natural selection is important in shaping the sex chromosome, there will be less variation on the X," Bustamante says. Since males have only one X chr...Researchers find gene mutation that causes infertility in male mice
...oduces sperm and egg cells for reproduction. These sex cells contain only one set of chromosomes that combine during conception and create an embryonic cell with two chromosome sets, one from each parent. The mutation leads to a change in an amino acid in Dmc1 that blocks meiosis in its tracks, preventin...The sturdier sex? -- Study by Pittsburgh scientists finds female stem cells work better
...ittsburgh School of Medicine. "Regardless of the sex of the host, the implantation of female stem cells...tigating regenerative medicine should consider the sex of the stem cells to be an important factor. Furthermore, investigations such as ours could lead to ...Pitt study notes decline in male births in the US and Japan
...ne a gene on the Y chromosome that determines the sex of a fertilized egg. Other environmental factors t...etailed studies should be carried out that examine sex ratio in smaller groups with defined exposures as a potential indicator of environmental contaminati...Disease can be our ally, not just our enemy, says new book by UCR evolutionary biologist
...get sexually transmitted diseases? Why do we have sex at all, rather than simply splitting off copies of...ites on mate choice and the evolution of secondary sex characters. Her popular writings include contributions to the Los Angeles Times , Natural History...JCI table of contents -- April 5, 2007
... precursors this was, in part, because the X and Y sex chromosomes failed to pair up and because there was no meiotic recombination. This study therefore identifies specific physiological functions for EWS and further analysis of the mice is likely to reveal further functions and might help elucidate som...Spiteful soldiers and sex ratio conflict among parasitoid wasps
...ernatively, if the sterile larvae are used by each sex to wage war against the other sex, then it should ...le larvae are female, suggesting a primary role in sex conflict." This work also explains the often strongly skewed sex ratios in these wasps, where female...Monitoring poisons in the environment -- a woolly matter
...ep. Another significant observation related to the sex of the sheep values for wool concentration of both lead and copper were significantly higher in male sheep, which has been linked to the effect of androgens on metabolism. Dr Sneddon comments, "Sheep wool evidently has potential as a bio-indicator...Ewwwww! UCLA anthropologist studies evolution's disgusting side
...es of 18 and 45. In addition to the scenario about sex between couples separated by great spans of age, t...women have been shown to be the most interested in sex and new experiences when they are the most fertile, their disgust reactions toward unusual forms of ...Fruit fly gene research may shed light on human disease processes
... or absence of the human Y chromosome that directs sex development, human females still need to determine...ntified the genes involved in counting Drosophilia sex chromosomes. Now, he and Avila have made another breakthrough, identifying a signaling pathway outs...Link between beef consumption during pregnancy and reduced sperm quality in sons
... human populations exposed to residues of anabolic sex hormones through meat consumption have never, to o...children are particularly sensitive to exposure to sex steroids. Therefore, the consumption of residues of steroids in meat by pregnant women and young chi...Salamanders suffer delayed effects of common herbicide
... and female organs by altering their production of sex hormones. Findings from Rohr's study, which was funded by the U.S Environmental Protection Agency, National Science Foundation, and the Kentucky Academy of Sciences, could have implications for global amphibian declines. "Salamanders, and amphibia...Could estriol be the elixir for MS?
...ues discovered the cause. They found that a female sex hormone called estriol, which is produced during pregnancy, was responsible for the suppression. Four years ago, Voskuhl followed that discovery with a pilot study in which 10 non-pregnant women with MS were given estriol, yielding what she described...Mitochondrial genes move to the nucleus -- but it's not for the sex
...onferred by sexual recombination. "The benefits of sex could have driven the transfer," he said. "There are powerful arguments out there for that. But that's just not what we saw." Brandvain, fellow graduate student Michael Barker, and their advisor, IUB evolutionary biologist Michael J. Wade, examine...