Fish throws away its genes as it grows

Whether it's its extraterrestrial looks or status as a "living fossil," there's always been something fishy about the sea lamprey. Now scientists have added another oddity to the creature's repertoire: The lamprey jettisons 20% of its genome during development.

Jeramiah Smith of the University of Washington, Seattle, first suspected something strange while piecing together the sea lamprey's genetic sequence. The postdoctoral fellow and his colleagues tried labeling live lamprey cells using a technique that detects broken DNA. "Every cell in the embryo was [labeled] as dying," he recalls. So he took a closer look to see what was going on and got a big surprise.

Working with Chris Amemiya of the Benaroya Research Institute at Virginia Mason in Seattle, the group found that lamprey sperm DNA had sequences not found in lamprey liver and that overall the sperm genome was millions of bases longer. The sperm DNA included a highly repetitive sequence called Germ1, and by monitoring the loss of Germ1 during development, Smith was able to track the genome's reorganization.

His group found that the egg and sperm have the full genome, but shortly after fertilization--about the time the new genome turns on--the genome starts to be pared down. By day two, the amount of Germ1 has decreased substantially. And by the time the larvae hatch, it's almost entirely disappeared, Smith's team reports online this week in the Proceedings of the National Academy of Sciences.

The group has also identified specific genes in sperm DNA that were lacking in liver. One of them, called SPOPL, may help stabilize the DNA-protein complex called chromatin, but Smith says he suspects "probably hundreds" more are missing from various places in the genome.

The discovery "opens up a whole new area of thought, as it's contrary to what you generally think happens in vertebrates," says Marianne Bronner-Fraser, a developmental biologist at the California Institute of Technology in Pasadena. Typically, vertebrates silence genes by modifying them or their surroundings chemically, not by getting rid of them.

Paring down might be economical, as each dividing cell has less DNA to replicate. But Smith thinks that the cell might be getting rid of genes that are good for the tissue destined to become egg and sperm--such as ones that stimulate rapid growth and proliferation--but which could make a specialized cell cancerous.

The work "is a very valuable contribution to our understanding of the dynamic nature of genome evolution," says embryologist Mark Martindale of the University of Hawaii, Honolulu.

Other organisms undergo genomic reduction, notes molecular biologist Guy Drouin of the University of Ottawa, Canada, who studies this phenomenon in tiny invertebrates called copepods. "The real breakthrough will come when someone is able to figure out the mechanism by which [genome reduction] occurs." One nice thing about lampreys, he says, is that they are easy to study--so perhaps these strange creatures will help solve the mystery.

Credit: Photo courtesy of Jeramiah J. Smith and Chris T. Amemiya

The Most Lifeless Place in the Ocean

Scientists have discovered what may be the least inhabited place in the ocean.
The seafloor sediments in the middle of the South Pacific have fewer living cells than anywhere else measured, a new study found.

Oceanographer Steven D’Hondt of the University of Rhode Island and colleagues took a boat out to the middle of the ocean and collected cores, or cylindrical samples of sediment, from the bottom of the sea about 2.5 to 3.7 miles (4 to 6 km) deep.

They found about 1,000 living cells in each cubic centimeter of sediment — a tally that is roughly 1,000 times less than in other seafloor sediments.

"People were previously just taking cores in parts of the ocean fairly close to shore and assuming their results were typical of the ocean as a whole," D'Hondt told LiveScience.

D'Hondt suspects that further research will show other areas out in the middle of the ocean may be similarly devoid of life. He and his team detailed their results in the June 22 issue of the journal Proceedings of the National Academy of Sciences.

The area they explored in the South Pacific is what's called a gyre, where the water is relatively still and nutrients are low.

The sparse microbes the scientists discovered appeared to be partially subsisting on hydrogen atoms released when radioactive elements at the bottom of the ocean decayed and broke apart water molecules.

This somewhat rare process produces only small amounts of food. The other half of the microbes' diet comes from organic matter that drifts from the surface down to the depths of the ocean.
"If you can support the concentrations we see on a food source that's basically half hydrogen from the radioactive splitting of water, then maybe you can support a few hundred cells in wet sediments on Mars or Europa," D'Hondt said. "It suggests that life is resilient enough under very low access to food."

(In above photo Oceanographers David C. Smith, Robert Pockalny and Franciszek Hasiuk prepare to remove a sediment core from the coring device.
Credit: Stephanie Forschner)

The secrets of ant sleep revealed

Queen ants dozily dream, while worker ants are forced to get by taking power naps, the first study of the sleeping habits of ants has revealed.

Queen fire ants fall into relatively long, deep sleeps and kip for an average of nine hours every day.

By contrast, workers sleep just half as much and get to rest by taking hundreds of short power naps.

This division of rest may help explain why queens live for years, while worker ants typically only live for months.

It also ensures that enough worker ants are awake at any one time to protect and serve the colony.

Deby Cassill of the University of South Florida in St Petersburg, US teamed with colleagues Skye Brown and Devon Swick of the same university, and George Yanev of the University of Texas in Arlington, US to study the sleeping patterns of the fire ant Solenopsis invicta.

"I decided to see just how lazy the queens really were," says Cassill.

She and her colleagues raised a colony of fire ants in their laboratory, and created an artificial chamber containing three queens, 30 workers and 30 large larvae. They placed a glass cover over the top of the chamber, allowing the ants to be continuously filmed from above.

Because fire ants generally live underground, the researchers expected that their sleep patterns would not be determined by light and dark cycles. And that is what they found.

Workers fell asleep at irregular intervals, and not at the same time. But the sheer number of incredibly short naps they took was striking.

On average, a single worker ant would take 250 naps each day, with each one lasting just over a minute. That equates to 4 hours and 48 minutes of sleep a day.

That also meant that 80 per cent of the workforce was awake and active at any one time.

"The large number and short naps by workers means that jobs in the nest never go unattended," says Cassill. "There is always a worker available when the need arises. When work is slow, workers sleep more."

Equally striking was the contrast between the sleeping habits of the workers and of the queens they served.

Queen dreams

The queens fell asleep at far more regular intervals than their subjects. In fact, the queens even synchronised their naps, with all three queens dozing together.

"It's very cosy," says Cassill. "The synchrony of queens occurs because, like hound dogs, they pile atop each other when they sleep. When awake, they separate."

On average, each queen would fall asleep 90 times a day, sleeping for just over 6 minutes at a time. That equates to over nine hours of sleep each day.

Queens also slept in two distinct ways.

Sometime they would just doze, with their antennae half raised and their mouths agape. When dozing, the queens could be easily roused by one another or by their workforce.

But often the queens would fall into much deeper sleep, with their antennae retracted and mouths closed.

Intriguingly, Cassill's team gathered evidence suggesting that the queen ants dream when sleeping deeply. Frequently, the queens would quiver their folded antennae when sleeping deeply.

This "rapid antennal movement (RAM) might be an analog to the rapid eye movement in vertebrates," the researchers write in the Journal of Insect Behavior.

Disposable workers

The function of sleep is still unknown.

But for ants, the lack of rest for the workers seems to help ensure the queens get to live a peaceful existence.

"Workers are a disposable caste whose job is to buffer the queen and her royal offspring from agents of death like exposure, starvation and predators. It is the workers who engage in the high risk behaviour, thus the queen lives a long life."

"Amazingly, queens can live six years before they die of old age. Whereas workers live six months to a year and then die of old age or some accident during foraging," says Cassill.

The queens of other ant species can live even longer, reaching up to 45 years. .

Tattooed teen suing over 56 facial stars

A BELGIAN teenager said she would sue a tattoo parlor which she claims covered half her face with stars while she was asleep, a report claims.

Kimberley Vlaeminck, 18, was left sporting 56 black stars of various sizes on the left side of her face, from nose to ear and brow to chin.

The young housewife said she had gone to the tattoo parlour in the western town of Courtrai and asked for three small stars on her face.

"I wanted him to tattoo on just three little points but he suggested three stars saying it would look prettier," Vlaeminck told local press.

"When he started the tattooing I didn't want to feel the pain and so I went to sleep. I had got up at five in the morning," she said.

"I woke up when he was starting to tattoo my nose and I saw what he had already done. I counted 56 stars, it's frightening," she told the Flemish daily Het Laatste Nieuws.

The young woman, who said she doesn't dare walk down the street, has decided to sue the tattoo parlour.

She said she also hoped to have her starry appearance reversed by laser treatment, which would cost thousands of euros.

Tattoo artist Rouslan Toumaniantz denied that his client had fallen asleep.

"She was awake the whole time, I don't use hypnosis or drugs. She agreed to it. The problems started when her father and his friend saw the tattoos," he told the paper.

Photo Credit : mirror.co.uk

What is WAP?

WAP - short for Wireless Application Protocol - is technology which allows you to access basic information on the internet from your mobile phone. This includes e-mail and information such as sport, traffic and news.

WAP is the name for the most popular type of mobile internet services.

It can be useful because if you are out and about you can still keep up-to-date with your e-mail, the latest news, sport, event guides and more.

So, let's say you want to check the football scores or see who has won Fame Academy you can go online wherever you are.

Normally we use a home computer to browse the web using a phone line but you can actually use your mobile phone to get lots of information off the web.

At the moment, these services are text-based - like news, sport, entertainment listings and weather so the pages don't look too pretty.

Getting WAP

When you connect to the internet from home you need a phone line and also an ISP (Internet Service Provider), the company you phone when you want to connect to the internet.

With WAP services you use your normal mobile network, for example Reliance, Airtel or Vodafone, and then register with a special ISP that offers mobile internet.

Each mobile network has its own service provider, for example Vodafone's is Vizzavi. If you are not sure who your network's service provider is you should contact your network.

If you use the WAP service to go online the cost is normally just added to your monthly bill.

WAP services are normally charged by the minute.

Check whether you can use WAP as part of any inclusive minutes you may have as this could be a cheaper way to access.

Mobile browsing

Once you have a service provider you can either use their WAP site or bookmark others.

By entering the address of the site you wish to use (like www.bbc.co.uk/mobile), you will be able to use your mobile phone keypad to surf around.

Because most mobile phone screens are really small and only display black and white you won't see a normal web page in all its colorful glory but you'll get a cut down version of the website.

The people who make web pages have to make separate versions for WAP phones so you may find that your favourite website doesn't have a WAP version.

Navigating

To get around sites you move up and down and select links in a similar way to the web using the keys of your mobile phone.

It's just like using the normal menus on your phone that you use to get text messages and change your phone settings but instead you are using them to move around the web.

If you want to have a go for free, try it out on BBCi WAP emulator.

Normally your WAP service provider will connect you directly to their internet pages but there's nothing to stop you entering the name of a different site, like BBCi's, and going there.