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Tag: "sperm" at biology news

Cigarette smoke alters DNA in sperm, genetic damage could pass to offspring

...t smoking can cause changes in the DNA sequence of sperm cells, alterations that could potentially be inher...re mouse or man, generate a constant supply of new sperm from self-renewing spermatogonial stem cells. Yauk, along with colleagues at Health Canada and McMa...

Studies to find better ways to preserve human eggs, ovarian tissue under way

...hniques, used successfully for decades to preserve sperm and embryos, to a more rapid method of cryopreserv...Slow cooling works well for simple tissue, such as sperm or even embryos, and for blood. “In blood, for example, conventional cryopreservation freezes the li...

Male-killing bacteria makes female butterflies more promiscuous

... to fatigue in males. They start producing smaller sperm packages. Unfortunately, the female butterflies in...h female mating frequency and the size of the male sperm package (Spermatophore) per copulation to find how female promiscuity was affected by the sex ratio....

Tracking sperm whales and jumbo squid

The sperm whale and its large prey, the jumbo squid, are amo...arine scientists reports the successful tagging of sperm whales and jumbo squid swimming together off Mexico’s Pacific coast—the first time that electronic t...

Researchers find gene mutation that causes infertility in male mice

...ein involved in meiosis, the process that produces sperm and egg cells for reproduction. These sex cells co...Dmc1 that blocks meiosis in its tracks, preventing sperm production. The mutant allele (one version of the pair of genes we inherit from each parent) is domi...

Early-stage sperm cells created from human bone marrow

...an bone marrow has been used to create early-stage sperm cells for the first time, a scientific step forwar...at will help researchers understand more about how sperm cells are created. The research published today (Friday, April 13 2007), in the academic journal R...

Manipulating nature: Scientists query wildlife birth-control method

... prevent either fertilization or the production of sperm and ova. Proponents of the technique, which was first tested nearly 20 years ago, regard it as more humane than the conventional methods of controlling wildlife populations, such as shooting, trapping, poisoning or viral diseases. It has drawn su...

Vasectomy may put men at risk for type of dementia

...n the body. Tiny tubes within the testes (in which sperm are produced) are protected by a physical barrier ...s into the blood. The immune system recognizes the sperm as invading foreign agents and produces anti-sperm antibodies in 60 to 70 percent of men. Weintra...

Phthalates now linked to fat, related health risks

... "Substantial declines in testosterone levels and sperm quality have been observed in the United States and other countries over the last several decades which and it urgently requires explanation," Stahlhut said. "While we can’t say yet that phthalates are a definite cause, I am certain they are on the ...

No-scalpel vasectomies by skilled surgeons may speed recovery

...e scrotum. Cutting or tying the vas, which carries sperm from the testicles, leaves a man infertile. Instead of making an incision, the no-scalpel technique uses a sharp instrument to puncture the skin. Advantages of puncturing rather than cutting the skin of the scrotum include less bleeding, bruising...

Penn researchers replace organ in adult mice using 'single-parent' stem cells

... cells - created from a single donor's eggs or two sperm - and, for the first time, successfully used them to repopulate a damaged organ with healthy cells in adult mice. Their findings demonstrate that single-parent stem cells can proliferate normally in an adult organ and could provide a less controver...

Study of planarians offers insight into germ cell development

...or the study of germ cells, precursors of eggs and sperm in all sexually reproducing species. The planarian Newmark studies, Schmidtea mediterranea, is a tiny creature with a lot of interesting traits. Cut it in two (lengthwise or crosswise) and each piece will regenerate a new planarian, complete with ...

New clues to how sex evolves

...ll replicates and then divides twice, resulting in sperm or eggs with just one set of chromosomes each. For meiosis to work properly, corresponding chromosomes must first identify each other, then line up accurately and stay together during the recombination process. Different organisms use different metho...

Genetic surprise confirms neglected 70-year-old evolutionary hypothesis

...ha, is one of the same genes that is essential for sperm motility in the flies, as well as in humans and other mammals. Masly's work shows a back door through which speciation can start. If the right genes jump around in the genome, a population can begin creating individuals that can't successfully mate ...

Queen bee promiscuity boosts hive health

...cks. "Even though just one male provides all the sperm that a queen needs for the rest of her life, queen honeybees go out on mating flights and obtain sperm from a dozen or more males," said lead author Thomas Seeley, Cornell professor of biology and chair ...

Scientists discover role for dueling RNAs

...into germ-cell spores that, like mammalian egg and sperm cells, have half the number of chromosomes. Yeast spores withstand this harsh environment far more ably than the larger cells from which they originate. But in some cases, flipping the meiotic switch can be catastrophic. If a cell with only one c...

Exposure to dioxins influences male reproductive system, study of Vietnam veterans concludes

...st several decades. These include a decrease in sperm production by almost 50 percent, a three- to four-fold increase in testicular cancer, an increase in the incidence of cryptorchidism (undescended testes, a condition where the testes are not in their normal location in the scrotum) and hypospadias (a...

Single molecular 'mark' seen as pivotal for genome compaction in spores and sperm

...nformation is passed from parents to offspring via sperm or eggs, also known as gametes. In some single-cel...tists saw the same activity during the creation of sperm in fruit flies and mice, suggesting that the mechanisms governing genome compaction are evolutionari...

Researchers create genetically matched embryonic stem cells for transplantation

...hods exist for deriving embryonic stem cells using sperm from men, but these techniques are as technically challenging and inefficient as somatic cell nuclear transfer, Daley says.) There are also potential safety concerns. Embryonic stem cells created through parthenogenesis have altered expression of c...

A new male-specific gene in algae unveils an origin of male and female

...ise to reproduction though the joining of distinct sperm and egg cells. The findings, which indicate that a...ed during evolution to participate in sex-specific sperm development, are reported by Hisayoshi Nozaki and colleagues at the University of Tokyo, Rikkyo (St....

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