sex in Biological News

Study finds role for parasites in evolution of sex

... issue of the American Naturalist suggests that sex may have evolved in part as a defense against parasites. Despite its central role in biology, sex is a bit of an evolutionary mystery. Reproducing ... the reproductive capacity of sexuals. Why then is sex the dominant strategy when the do-it-yourself ...

Female human embryos adjust the balance of X chromosomes before implantation

... stem cell research. Males and females have two sex chromosomes: X and Y. While females have two X ... into RNA. Other probes were used to detect the sex and chromosomal status of each embryo. Ms van ... the embryo. A recent publication showed that the sex ratio of children born after blastocyst transfer ...

Older men more likely than women to die after pneumonia

... may have important implications for understanding sex differences in life expectancy. "Our study ... an important target for interventions to reduce sex disparities in the outcomes of infections," said ... will continue to examine relationships between sex and gene variations in CAP, sepsis and survival. ...

The story of X -- evolution of a sex chromosome

... a very active role in the evolutionary process of sex chromosome differentiation," said Bachtrog, an ... for the first time the flip side of the sex chromosome evolution puzzle: The X chromosome ... do set aside a pair of chromosomes to specify sex from fruit flies to mammals and some plants the ...

Small RNAs can play critical roles in male infertility/contraception

... into the reproductive workings of the male sex chromosome that may have significant implications ... and also in sperm formation. "The sex chromosome silencing in meiotic male germ cells ... phenomenon, which has been termed meiotic sex chromosome inactivation. I was surprised when we ...

Gene exchange common among sex-manipulating bacteria

... one generation to the next and manipulate the sex quotas among the infected animals so that more ... cell and that they now use them to manipulate the sex quotas among the insects. "With the help of ... of genes that are thought to be important for sex manipulation," says Lisa Klasson, one of the ...

Cutting-edge amfAR grants fight HIV/AIDS in the lab and on the phone

... Nyoni will recruit a small number of men who have sex with men (MSM), who in turn will recruit other ... program: Men involved in transactional sex with other men represent an important source of ... and prevention intervention in which male sex workers receive information both face-to-face as ...

Changing sexes on the sea floor

... coral (known as a fungiid coral) switches its sex so that most of the population becomes male. The ... "We believe, as with orchids and some trees, sex change in corals increases their overall fitness, ... apply to humans, even those who have opted for a sex change. While admired for their beauty by ...

Why don't more animals change their sex?

... born, live out their lives and reproduce as one sex or the other. However, some animals live as one sex in part of their lifetime and then switch to the ... four decades of research that established why sex change is advantageous, the question remained why ...

Attitudes towards assisted reproduction and preimplantation genetic diagnosis

... such as using the technique to choose a baby's sex (with scores below 3 points in almost every ... from 0 to 10). Conversely, its use to choose the sex of a future baby meets with widespread rejection ... the use of in vitro fertilization to choose the sex of a baby provokes outright rejection in all the ...

Boy or girl? It's in the father's genes

... it," Mr Gellatly explains. Men determine the sex of a baby depending on whether their sperm is ... more X or more Y chromosomes, which affects the sex of his children. On a larger scale, the number of ... the number of men with more Y sperm affects the sex ratio of children born each year. Sons or ...

U of Minnesota researcher finds link between aggression, status and sex

... and time, the higher status men have, the more sex or better-quality partners they may have," said ... Results showed that if men have status or sex on their minds (e.g., they are thinking about a ... slight seems much more substantial when a man has sex or status on his mind. Men are especially likely ...

CSHL scientists discover a new way in which epigenetic information is inherited

... The piRNAs are found only in cells of sex organs and partner up with proteins called Piwi ... gametogenesis the process of creating viable sex cells and can result in sterility. Piwi proteins ... piRNAs form something akin to an immune system in sex cells that guards against transposon-inflicted ...

Two from one: Pitt research maps out evolution of genders from hermaphroditic ancestors

... hermaphroditic genes that led to male and female sex chromosomes. With the ability to breed but spared ... test of the theory of the early stages of sex chromosome evolution and part of the process of ... have the opportunity to observe the evolution of sex chromosomes in plants because that development is ...

December 2008 highlights from Biology of Reproduction

... determine the C57BL/6J alleles modifying gonadal sex determination and germ cell fate. Nonetheless, ... importance of genetic context in the analysis of sex differentiation pathways. Susan Y. Park, ... Mice: Consequence of the C57BL/6J Strain on sex Determination. Biol Reprod 2008; ....

Female embryonic sexual development driven by universal factor

... or SRY gene, they realized that the mechanisms of sex determination were more complex than previously ... R-spondin1, experienced a partial female-to-male sex reversal: They formed ovaries, but with male ... R-spondin1 genes had similar malformations of the sex organs. Other studies had indicated that ...

American Chemical Society's Weekly PressPac -- Aug. 27, 2008

... of unusual proteins in a small group of Kenyan sex workers that appear to be associated with ... and colleagues note that 140 of more than 2000 sex workers studied in Nairobi, Kenya, appear ... in the Cervical Mucosa of HIV-1-Resistant sex Workers" DOWNLOAD FULL TEXT ARTICLE ...

Sex hormones link to heart risk

... disease compared with women of a similar age and sex hormones are to blame, according to a new ... the sex-specific effects of naturally occurring sex hormones. The research by Dr Tomaszewski ... study. The researchers looked at ways that the sex hormones - estradiol, estrone, testosterone and ...

Fish with temperature-dependent sex determination face global warming

... In vertebrates with separate sexes, sex determination can be genotypic (GSD) or ... of males and females in a population is the sex ratio, a key demographic parameter crucial for ... increasing temperatures generally affecting the sex ratio of a species in one of three ways: ...

Sex and lifespan linked in worms

... A group of scientists who set out to study sex pheromones in a tiny worm found that the same ... The researchers set out to identify the sex pheromone that attracts male C. elegans worms ... development and reproduction. To identify the sex pheromone, the researchers tested mixtures of ...

U of T discovers environmental factors linked to sex ratio of plants

... markers (known DNA sequences) to identify the sex of seeds. The team investigated six natural ... "The plant has strongly female-biased flowering sex ratios in these populations. We wanted to find ... mating environment of plants can influence the sex ratios of plants females produce," added Barrett. ...

Diet prior to pregnancy determines sheep's gender

... important factor when it comes to influencing the sex of the offspring "Our study ruled out body ... polyunsaturated fatty acid intake, can skew the sex ratio towards males in a farm species." These ... period could provide a means of controlling the sex ratio of offspring born to a herd or flock." ...

X chromosome exposed

... Hinxton, UK, have revealed new insights into how sex chromosomes are regulated. A chromatin modifying ... for the fact that males have only one copy of the sex chromosome X, while females have two. The enzyme distinguishes between male and female sex chromosomes in fruit flies and binds to different ...

University of Minnesota to host world's largest conference on evolution

... of the 2005 best-selling book, "Dr. Tatiana's sex Advice to All Creation," which caused a pop ... Judson's guide to the evolutionary biology of sex in the animal kingdom takes a lighthearted look ... public talk on "The Art of Seduction: Evolution, sex and the Public" at 4 p.m. Sunday, June 22 at the ...

Scientists decipher fruit tree genome for the first time

... the sequencing of the determinant region of the sex in the sexual chromosomes of papaya and whose ... implement a research work in the UGR directed to sex early diagnosis in vegetal species of economic ... as for the study of other molecular aspects of sex Biology in plants. ...

A new analysis method allows to find out the sex of the baby from the second month of pregnancy

... to develop a genetic trial that identifies the sex of the foetus from the eighth week of pregnancy ... forth or fifth month of pregnancy to find out the sex of their future baby, involves a great scientific ... these cases, the possibility of determining the sex of the baby as soon as possible, would avoid the ...

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

... lab are studying the effects of male pregnancy on sex roles and sexual selection of mates and are ... Male pregnancy has interesting implications for sex roles in mating, Jones explained, because in most ... so you usually see the evolution of secondary sex traits in males (for example, a peacocks tail or ...

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

... lab are studying the effects of male pregnancy on sex roles and sexual selection of mates and are ... Male pregnancy has interesting implications for sex roles in mating, Jones explained, because in most ... so you usually see the evolution of secondary sex traits in males (for example, a peacocks tail or ...

Biology of Reproduction highlights

... body of evidence suggests a maternal influence on sex determination: dominant human females conceive ... issue of Biology of Reproduction , find that the sex of bovine embryos positively correlates with ... to be a sister, dont aggravate your mother. sex of Bovine Embryos May Be Related to Mothers' ...

Is DNA repair a substitute for sex?

... Bdelloid rotifers have been able to give up sex and survive because they have evolved an ... the kinds of changes into the gene pool that sex usually does. (For example, a gene coding for ... may provide enough of the advantages of sex that bdelloids can survive, Mark Welch says. ...

Fungi can tell us about the origin of sex chromosomes

... between the parts of DNA that determine the sex of plants and animals and the parts of DNA that ... in studies of the evolutionary development of sex chromosomes. In the plant and animal kingdoms ... sexes, that is, bearers of either many tiny sex cells (males) or a few large ones (females). In ...

High levels of estrogen associated with breast cancer recurrence

... studies that have looked at the link between sex hormones in the blood and cancer recurrence, she ... was bound to transport proteins (such as to the sex hormone binding globulin, or SHBG) and how much ... influence the relationship between circulating sex hormones and risk of breast cancer recurrence, ...

Total, genetically-based recall

... system strength, physical adaptations and even sex differences. These qualities drive the nature ... question of human predisposition: Does ones sex influence his or her ability to remember everyday ... findings did in fact determine significant sex differences in episodic memory, a type of ...

Evolution of the sexes: What a fungus can tell us

... come in boy and girl varieties, but they do have sex differences. In fact, a new finding from Duke ... 10 issue of Nature. Fungi do not have entire sex chromosomes, like the familiar X and Y ... sexual identity in humans. Instead, they have sex determining sequences of DNA called "mating-type ...

How do you know whether you are male or female?

... at Texas A&M University studied the mechanism of sex determination in the fruit fly, Drosophila ... chromosomes (the autosomes) that determined the sex of a fly embryo. However, this new paper ... is the number of X chromosomes that is important. sex is determined during a very specific and short ...

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

... weve found a reversal of these stereotypic sex roles. Such role reversals may occur in ... an ideal opportunity for studying the dynamics of sex roles in promiscuous mammals, Bro-Jrgensen said, ... not regard coyness as the only natural female sex role just as we should not expect that it is ...

Worms take the sniff test to reveal sex differences in brain

... clear that they either are more prevalent in one sex than the other, or they manifest themselves ... professor of Biomedical Genetics. We think that sex differences in the brain may play a role. If we ... Portman said. The team is focusing on sex differences in the nerve cells of the critters, ...

Humans and monkeys share Machiavellian intelligence

... eat first and then have the leftovers; they have sex only when the dominant monkeys are not looking. ... reproduction. They make sure they have lots of sex with the alpha male to increase the chances he ... 6 months later. But while they have lots of sex with the alpha male and make him think hes going ...

A new explanation for evolutionary changes in genetic sex-determination systems

... early stage. Often this key decision is made by sex determination genes on the sex chromosomes. The genes involved in sexual ... little during evolution. In contrast, the sex determination genes and ...

Genes from the father facilitate the formation of new species

... gene for this sexual preference is found on the sex chromosome that is inherited from the father and ... preference is determined by genes located on the sex chromosome, says Anna Qvarnstrm. In birds, in ... that are the so-called heterogametic sex. Their sex chromosomes are called ZW and correspond to XY in ...