Damage to sperm DNA affects older men's chances of fathering children
Copenhagen, Denmark: Damage to DNA in sperm is significantly higher in older men than in those... of increased female factor infertility, increased sperm DNA damage, low levels of DNA repair, and increased abnormalities in conventional semen parameters p...Environmental chemical cocktail may sabotage sperm
...od have subtle but potentially damaging effects on sperm fertility. Professor Lynn Fraser told the 21st an...legumes), on human sperm, she found that the human sperm were much more sensitive to it than mouse sperm. Even tiny doses could cause human sperm to "burn o...Study in Royal Society journal on holly as an indicator of climate change
...bowers; in this species males provide females with sperm but no help with parental care. We studied how female satin bowerbirds choose which males to mate with. Our results suggest that females' decisions about which males' bowers to inspect closely are based on the males' sizes and the rates at which they...Meaningless sex? Male mounting reduces sexual promiscuity of females
... with multiple males, leading to the phenomenon of sperm competition--the competition between the ejaculate...les to successfully fertilize eggs. The battles of sperm competition occur at the cellular and molecular levels and involve the production of sperm-associate......eratures from 20C upwards. Females therefore carry sperm until a suitable temperature arises for fertilisation. Research showed that male fish are adapted to their environmental temperatures; some "perform" better in colder, others in warmer environments. Short-term adjustments to their muscle structure an...Elderly mice yield clues to the process of growing old
..., and loss of male germ cells that lead to reduced sperm production and infertility. Intriguingly, the mice develop symptoms of old age, notably gray hair and hair loss, more commonly seen in humans than mice. Prolla suggests that new studies of mice engineered to have fewer than normal mitochondrial DNA...Multi-species genome comparison sheds new light on evolutionary processes, cancer mutations
...rms of evolution. When chromosomes break in egg or sperm cells, opportunities arise for the rearrangement of DNA in the resulting offspring. Such inheritable rearrangements may be lethal or cause disease. However, in some cases, the breaks may lead to the production of new or altered proteins with potentia...Research suggests fitness of Florida panthers improved by limited breeding with Texas animals
...r an array of genetic abnormalities, including low sperm counts and heart defects. "It turns out that purebred kittens don't survive very well," he said. "They die in very high numbers. Once you get new blood, those defects disappear from the population. Hybrids are better than inbred animals." The paper a...Decisions, decisions: Male or female?
...ized "germ cells" whether to develop into a male's sperm or a female's eggs. Present in both male and female embryos, germ cells are the precursors to both sperm and eggs. Unable to "decide" on their own which to become, however, germ cells must take "advice" fr...A new view of human-chimpanzee genome differences
...ive segments of DNA occur during the production of sperm or eggs because of a predisposition of certain sites along the chromosomes to undergo breakage and rearrangements, Eichler explained. The resulting segmental duplications are evolutionarily important because they give rise to extra copies of genes th...Human Y chromosome preserves itself better than the chimp Y
...art of the mating game, chimpanzees make much more sperm than humans do, so their testes need to be operating at high capacity. As a result of the newest research, Page added, "we can also draw some inferences about that common ancestor" shared by humans and chimps some 6 million years ago. By examining an...New genome comparison finds chimps, humans very similar at DNA level
...ound, transmission of nerve signals, production of sperm and cellular transport of electrically charged molecules called ions. Researchers suspect the rapid evolution of these genes may have contributed to the special characteristics of primates, but further studies are needed to explore the possibilities....One shot: A molecular movie of events that enable sperm to penetrate egg's coating
...ers have capitalized on the unique properties of a sperm cell to follow cell membrane fusion as it occurs d...dvantage of the cellular specialization that gives sperm one irreversible chance to fertilize an egg. The group followed the sperm's secretion of the enzyme......to natural fertilization where nuclei from egg and sperm are combined. In doing so, Kono hopes to decipher the molecular mechanisms underlying imprinting. He showed a method for converting maternally imprinted genes to genes that can basically behave as paternal types, thereby succeeding in generating a li...Study in Royal Society journal on first observation of giant squid in the wild
...ve flown, but before swarming. This may give their sperm the first class accommodation in the oviduct throu... 24105, Germany Egg-independent release of stored sperm in female Drosophila melanogaster by Professor MC Bloch Qazi and Professor MF Wolfner Sperm stored ...Researchers to gain wider access to knockout mice
...ll be stored in the form of frozen embryos, frozen sperm and frozen embryonic stem (ES) cells, will be delivered to NIH-funded mouse repositories that supply mice to universities, medical schools and research labs all over the world. When researchers express interest in obtaining a certain knockout mouse l......hrodites both male and female and make their own sperm and eggs. Rhythmic contractions control how the eggs are pushed down the tube-like gonadal sheath and into the spermatheca, which contains sperm. When vav-1 is disabled, the worms "have almost no progeny," Maricq says. "They don't have the proper ...Sperm trading can resolve hermaphrodite mating conflicts
...ting conflicts by "trading sperm," that is, giving sperm only when the mating partner follows suit. However...of performing a "dry" copulation--that is, without sperm transfer. Sea slugs that mated with such a "cheating" partner interrupted sexual intercourse signifi...EU research suggests that PCBs damage sperm but finds no dramatic effect on male fertility
...DDT[3] but found that it did not appear to damage sperm DNA. The impact of persistent organochlorine pollu... set out also to see whether these two POPs damage sperm by altering its chromatin integrity. (Chromatin is the DNA and associated proteins that make up a ch......team found that genes involved in immune function, sperm and egg production, sensory perception and transcription factors (proteins that control which genes are turned on or off) have been particularly affected by positive selection and show rapid evolution in the last 5 million years, when humans shared a...