Sexual in Biological News

Sex in the Caribbean: Environmental change drives evolutionary change -- eventually

... Hungry, sexual organisms replaced well-fed, clonal organisms in ... that if a species could shift from clonal to sexual reproduction it survived. Otherwise it was ... clearly see the first individual that founded a sexual colony, while a clonal colony preserves the ...

Parasitic worms make sex worthwhile

... the "Red Queen Hypothesis" of sex, which suggests sexual reproduction allows host species to avoid ... wondered why clonal reproduction does not replace sexual reproduction in natural populations. Our studies ... part of the answer, because genetically variable sexual individuals might be more likely to escape ...

Study finds role for parasites in evolution of sex

... has the ability to reproduce on its own. But in sexual species, two individuals have to combine in order ... wipe out the whole population. On the other hand, sexual offspring are genetically unique, often with ... destroy all. That, in theory, should help sexual populations maintain stability, while asexual ...

Why do we choose our mates? Ask Charles Darwin, prof says

... Darwin's beliefs about the choice of mates and sexual selection being beyond mere chance have been ... as Jones states in his paper, "Mate Choice and sexual Selection: What Have We Learned Since Darwin?" in ... And also, what is the driving force behind sexual selection? We have an unprecedented ability to ...

Stress puts double whammy on reproductive system, fertility

... piece of the puzzle about how stress causes sexual dysfunction and infertility. Scientists know ... suppresses sperm count, ovulation and sexual activity. The new research shows that stress ... attribute much of this stress effect on sexual function to an increase in glucocorticoids - ...

Is this the beginning of the end of plant breeding?

... of their animals or crops without the lottery of sexual reproduction. Clonal reproduction of crop species ... into the second meiotic divisionin the sexual plant Arabidopsis thaliana. By combining a ... of asexual reproduction possible in a normally sexual species. Turning meiosis into mitosis is not ...

Single women gaze longer

... of Human Nature , women both with and without sexual partners showed little difference in their ... However, the women who did not have sexual partners spent more time evaluating photos of ... No such difference was found between men who had sexual partners and those who did not. "These ...

Society for Prevention Research Meeting in Washington, D.C., May 27-29, 2009

... well as specific health behaviors, such as risky sexual activity, drug use, healthy eating and physical ... topics are: Youth Suicide Prevention, Preventing sexual Violence, Early Initiation and Health-Risking sexual Behavior, and New Drug Prevention Approaches. ...

Yeast missing sex genes undergo unexpected sexual reproduction

... yeast Candida is able to complete a full sexual cycle in a test tube, even though it's missing ... reports that eight Candida species which have a sexual cycle were missing many of the genes related to ... genes responsible for meiosis, the process of sexual cell division that reduces chromosomes to half ...

Sexual harassment from males prevents female bonding, says study

... The extent to which sexual harassment from males can damage relationships ... Society B , the research uncovers the effect of sexual harassment on the ability of female fish to form ... have previously observed a very high level of sexual harassment from males towards females. The ...

Male impotence drugs may deserve a second look in women

... potential in the 40 percent of women who report sexual dysfunction, researchers say. In one of the ... clitoris the blood needed to produce a satisfying sexual experience, Medical College of Georgia ... response likely provides more evidence that sexual function is more complex in females, says Dr. R. ...

Genes from tiny marine algae suggest unsuspected avenues for new research

... that Micromonas contains genes associated with sexual reproduction (as opposed to simply dividing into ... that we have the sequences for those genes [for sexual reproduction], we could look for them being ... could try to figure out the conditions triggering sexual reproduction and the ecological avenues it opens ...

African-Americans aware and accepting, but often do not receive, the HPV vaccine

... the human papillomavirus, which is spread through sexual contact, they would be more likely to have early sexual relations. "I doubt that whether or not she ... 60 percent of them had had their first sexual encounter when they were 14 years old. Of ...

Rice University psychologist finds women's brains recognize, encode smell of male sexual sweat

... found that socioemotional meanings, including sexual ones, are conveyed in human sweat. Denise ... volunteers processed and encoded the smell of sexual sweat from men. The results of the experiment ... chemosensory communication, including human sexual sweat. Scientists have long known that animals ...

Female embryonic sexual development driven by universal factor

... also is vital to female but not male embryonic sexual development, scientists report this month. The ... to a controversial hypothesis about mammalian sexual development. In the beginning in terms of their sexual organs all embryos look alike, said Illinois ...

Low sperm count may be associated with prenatal testosterone excess

... Exposure to an excess of sexual steroids, like testosterone, during fetal ... and when that environment is exposed to excess sexual steroids, it may have a significant deleterious ... fertility." Prenatal exposure to excess sexual steroids can occur in two ways, said Dr. ...

In spiders, size matters: Small males are more often meals

... small relative to females. Much research on sexual cannibalism has focused on a few extreme cases involving sexual selection and sperm competition. However, by ... male relative to the female (often referred to as sexual size dimorphism) determines how ...

Lightweight and long-legged males go the distance for sex

... success). "Our findings are a rare example of sexual selection favoring a suite of traits that promote ... " this is exciting because it suggests that sexual selection for smaller, more mobile males could be responsible for some of the impressive sexual difference in body size in this species." ...

How 'secondary' sex characters can drive the origin of species

... is an investment trade-off between secondary sexual characters and primary sexual characters," Moczek said. "As horns get bigger, ... directly involved in mating are known as primary sexual characters, whereas combat structures like horns ...

Male fish deceive rivals about their top mate choice

... a rival, the tricky males direct their first sexual advances toward females that really aren't their ... his team, showing that male Atlantic mollies curb sexual activity when other males are around, acting as ... They then introduced a male and observed his sexual advancesincluding nipping and mating attemptsfor ...

Caltech researchers find dual-use sexual attraction and population-control chemicals in nematodes

... as both a population-control mechanism and a sexual attractant. The discovery, published online ... dubbed ascr#2, ascr#3, and ascr#4, induced sexual excitement among males, but only when the ... 100 to 1000 times stronger, males were repelled, sexual reproduction ceased, and existing worm larvae ...

HIV infection stems from few viruses

... virus (HIV), the version responsible for sexual transmission, in unprecedented detail. The ... among billions of HIV variants only a few lead to sexual transmission. Earlier studies have shown that ... those viruses that are responsible for sexual transmission of HIV-1. For the first time we can ...

Scientists decipher fruit tree genome for the first time

... in the tree of life and the recent discovering of sexual chromosomes in its genome, Carica papaya is an ... organism for the study of the evolution of sexual chromosomes in plants. Dr Navajas Prez, who at ... of the determinant region of the sex in the sexual chromosomes of papaya and whose research career ...

Human vision inadequate for research on bird vision

... many studies looking for factors that influence sexual selection in birds. However, is it reasonable to ... The results mean that many studies on sexual selection may need to be re-evaluated, says ... are not only significant for basic research on sexual selection. They also illustrate the risks of ...

Male seahorses are nature's Mr. Mom, Texas A&M researchers say

... the effects of male pregnancy on sex roles and sexual selection of mates and are trying to understand ... said. It provides a unique opportunity to study sexual selection in this reversed context. To study ... this system results in very strong competition in sexual selection, and female gulf pipefish have evolved ...

Male seahorses are nature's Mr. Mom, Texas A&M researchers say

... the effects of male pregnancy on sex roles and sexual selection of mates and are trying to understand ... said. It provides a unique opportunity to study sexual selection in this reversed context. To study ... this system results in very strong competition in sexual selection, and female gulf pipefish have evolved ...

In promiscuous antelopes, the 'battle of the sexes' gets flipped

... In some promiscuous species, sexual conflict runs in reverse, reveals a new study ... males play hard to get. The classical view of sexual conflict holds that males, for whom reproducing ... Bro-Jrgensen added. He noted that this reversed sexual conflict might not be a rarity in the animal ...

New evidence for female control in reproduction

... be the molecular mechanism behind post-copulatory sexual selection, in which females that have mated with ... by being the faster swimmer. With post-copulatory sexual selection, the female is in control, her oviducts ... sperm alive. This may be an aspect of post-coital sexual selection since sperm may remain viable in the ...

University of Minnesota releases first ever comprehensive report of the health of college students

... mental health and obesity to financial health and sexual health. It also looks at alcohol use, smoking, ... 7.1 percent report using illicit drugs. sexual violence More than one in five or 22.4 percent of female students report experiencing a sexual assault in their lifetime with 6.8 percent ...

Family conditions may affect when girls experience puberty

... creating conditions that speed puberty as well as sexual activity. These stressors include marital ... to the theory, children adaptively adjust their sexual development in response to the conditions in ... in first grade, and the development of secondary sexual characteristicssuch as breast budding and the ...

Simple reason helps males evolve more quickly

... to win the best mates, a concept known as sexual selection. Why males are in evolutionary ... that could be working in cooperation with sexual selection to help males evolve more quickly. ... pathway helps males respond to the pressures of sexual selection, ultimately enabling them to win ...

Scientists alter sexual orientation in worms

... worms of the same sex part of a study that shows sexual orientation is wired in the creatures brains. ... Nov. 6 print edition. "The conclusion is that sexual attraction is wired into brain circuits common to ... the same nerve cells have been rewired to alter sexual preference, he adds. Our conclusions are narrow ...

Are some men predisposed to pedophilia?

... were shorter on average than males without a sexual attraction to children. The study, published in sexual Abuse: A Journal of Research and Treatment, ... men who were assessed for pedophilia or other sexual disorders between 1995 and 2006 at the Kurt ...

The benefits of 80 million years without sex

... sex, these animals lack many of the ways in which sexual animals adapt over generations to survive in ... copies that would have the same DNA sequence in sexual creatures can be quite different from each other ... of gene function in this way cant happen in sexual organisms, which means there could be some ...

Why do males and females frequently differ in body size and structure?

... Size & Gender Roles: Evolutionary Studies of sexual Size Dimorphism" (Oxford University Press, 2007), ... We see this reflected in fantastic patterns of sexual dimorphism that we have only begun to appreciate. ... Size & Gender Roles: Evolutionary Studies of sexual Size Dimorphism." ...

Study finds Viagra increases release of key reproductive hormone

... physical effects besides increasing blood flow to sexual organs, says study author Meyer Jackson, a ... released during orgasm and has been linked to sexual arousal. Oxytocin release is regulated by an ... spontaneously, they enhance the response to sexual stimulation," he says. "The same thing is ...

News tips from the Journal of Neuroscience

... filopodia. KisspeptinGPR54 Signaling in sexual Differentiation Alexander S. Kauffman, Jin Ho ... hormones exert influence on the development of sexual dimorphism in the brain. This week, Kauffman et ... GPR54- deficient males showed the expected male sexual behavior after treatment with testosterone, but ...

Beautiful plumage: Feather color and sex start the species revolution

... mate, but these differences stop them recognizing each other as potential sexual partners. This is evidence of incipient speciation: the beginning of the ... can cause colour change in birds, affecting the selection of potential sexual partners. This leads to reproductive isolation and eventually speciation, ...

Vaccine blocks malaria transmission in lab experiments

... Antibodies induced by Pfs48/45 protein vaccine effectively blocked the sexual development of the malaria-causing parasite, Plasmodium , as it grows within the mosquito. sexual development is a critical step in the parasite's life cycle and necessary ...

NIH expands Human Microbiome Project; funds sequencing centers and disease projects

... University Purdue University at Indianapolis Male urethra: Puberty, sexual Activity and Sexually Transmitted Diseases $820,000 Samples will be ... to characterize the male urethral microbiome and its relation to puberty, sexual activity and sexually transmitted disease. Claire M. Fraser-Liggett, ...