Tag: "sex" at biology news
Bird sex is something else
...difference is genetic. Species with differentiated sex
chromosomes (X and Y in humans, for example) get a... males and females get different-sized portions of sex
chromosome genes with a balancing act geneticists call dosage compensation. But research published ...
Gene controlling circadian rhythms may be involved in onset of bipolar disorder
...d by naturally rewarding experiences such as food, sex
and the use of certain drugs. This also resulted in the mice going back to normal behaviors. "While the Clock gene is expressed throughout the brain, it's really only been studied in one particular brain region, which is the one that's involved i...
No sex for 40 million years? No problem
A group of organisms that has never had sex
in over 40 million years of existence has neverthe...ed today. The study challenges the assumption that sex
is necessary for organisms to diversify and provides scientists with new insight into why species ev...
Do you need sex to be a species?
... ponds, and other freshwater repositoriesabandoned sex
perhaps 100 million years ago, yet have apparently...earchers argue, t his study "refutes the idea that sex
is necessary for diversification into evolutionary species." They hope others use their approach to ...
Neighbors gone, fruits gone, species gone
Neighbors gone, sex
gone, fruits gone, species gone. This is the ultra-short conclusion of the findings in a study by Dennis Hansen, Heine Kiesby, and Christine Mller from Zurich University, and Carl Jones from the Mauritian Wildlife Foundation, who found that an endang...
New mathematical model to add rigor to studies of disease genetics and evolution
...chromosomes stay separated in these pairs. But the sex
cells (sperm and egg) each carry only one copy of each chromosome, a mix of the two inherited chromosomes produced by genetic recombination. During the creation of new sperm or egg cells, paired chromosomes line up and exchange stretches of DNA be...
Prefrontal cortex loses neurons during adolescence
...ring adolescence. It is also the first to document sex
differences in the number of neurons in the PFC. T...h perception. But no other studies have looked for sex
differences in the number of neurons in the prefrontal cortex. It is unclear whether sex
JCI table of contents -- March 8, 2006
...ransplant donor and recipient were not of the same sex
it was determined that the MSCs were nearly all (97.2% 2.1%) of donor origin, indicating that they had persisted in the tissue since the time of transplantation. This study indicates that the lung contains a population of long-lived tissue-resident ...
Too much weight spells double trouble for couples trying to conceive
... from the time a couple starts to have unprotected sex
with an intention to conceive. Earlier research has already shown that weight can affect fertility in both women and men, individually. However, this is the first study to look at the effect on fertility of overweight and obesity in couples. Ms Ram...
Independent panel to evaluate widely used chemical, Bisphenol A
...ata indicate that BPA may mimic the natural female sex
hormone, estradiol. Exposure to the general population can occur through direct contact to BPA or by exposure to food or drink that has been in contact with material containing BPA. The Center for the Evaluation of Risks to Human Reproduction (...
New research finds that a natural family planning method is as effective as the contraceptive pill
...und that if the couples then either abstained from sex
or used a barrier method during the fertile period... in the study, including those who had unprotected sex
during their fertile period, 1.8 per 100 became unintentionally pregnant. The lead author of the r...
Scientists warn of climate change risk to marine turtles
...tle populations are to changes in temperature. The sex
of marine turtle hatchlings is determined by the temperature of eggs during incubation, with warmer temperatures producing females and cooler conditions producing males. Temperatures during nesting also need to be at the right level for eggs to devel...
Penn researchers replace organ in adult mice using 'single-parent' stem cells
...rapeutic route for both genders; members of either sex
can use this technique to produce compatible stem cells, much like you might donate blood for your own use in advance of an operation." Parthenogenesis, the act of creating an embryo without fertilization, is common in some plants, insects and anim...
Ready when you are
...ks so while they could see members of the opposite sex
through the glass, they could not use other senses to respond to one another. Dr Walling continues: 'It's well established that sexual maturation in swordtails is highly variable, occurring anywhere between four and 20 months of age even though the...
Psychologist explains the neurochemistry behind romance
...ession, and fear," Kristal said, adding that while sex
attractant pheromones may explain changes in libido, they don't explain why we choose a specific person for a mate. "In humans, specific mates are more probably chosen on the basis of other sensory cues: visual, regular olfactory, auditory and tactil...
Good for the goose, not so great for the gander
... "For a long time, we only did experiments in one sex
or the other, depending on what was convenient," s...ow, on a genetic level, the evolution of aging and sex
may be inextricably linked. Tower published the theoretical model in the September Mechanisms of A...
Adaptation to global climate change is an essential response to a warming planet
... same distaste as the religious right reserves for sex
education in schools both constitute ethical compromises that will only encourage dangerous experimentation with undesired behavior," the policy experts state. Over the years, mitigation was favored as the global response to climate change, and ad...
Male-killing bacteria makes female butterflies more promiscuous
...to females. The researchers assessed the natural sex
ratio in 20 populations and combined this data wit...to find how female promiscuity was affected by the sex
ratio. They found that the size of the Spermatophore was key to female promiscuity. However, female ...
Brain's reward circuit activity ebbs and flows with a woman's hormonal cycle
Fluctuations in sex
hormone levels during women's menstrual cycles aff...gesterone are present. "These first pictures of sex
hormones influencing reward-evoked brain activity in humans may provide insights into menstrual-rela...
How does one sex grow larger than the other?
...and females grow at the same rate, then the larger sex
has to extend its growth period. Alternatively, the larger sex
can grow faster. A group of 13 researchers from 10 countries investigated the latter questions us...
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