Tag: genetics

Gertie the Hen "Sex-Changes" into Bertie the Rooster

By Patrick Morgan | April 19, 2011 2:46 pm

Normally, chicken-keepers don’t sweat it when their hens go through short egg-laying dry-spells. But when an egg-less hen grows a wattle in a matter of weeks and starts crowing at the rising sun, it may be time to worry. That’s what went through a British couple’s minds this past year, when their pet hen Gertie began looking and acting like a rooster.

It all started last November, when Jim and Jeanette Howard of Huntingdon, England, noticed that Gertie stopped laying eggs. “Then a few days later I heard her try to crow,” Jeanette Howard told the BBC. “She wasn’t very good at it at first, but she’s progressed nicely.” Gertie then got heavier and developed a wattle under her chin in the next few weeks. And as her feathers grew back during her molt, they were a darker brown than before. Sporting a scarlet cockscomb and a rooster-like strut, Gertie is now outwardly indistinguishable from a cockerel. Read More

MORE ABOUT: gender, genetics, hormones, sex

The Genetic Gamesmanship of a Seven-Sexed Creature

By Patrick Morgan | March 4, 2011 9:40 am

What could be better than two types of sexes? For one organism, the answer isn’t three, but seven! And to top it off, these seven sexes aren’t evenly distributed in a population, although researchers have now developed a mathematical model that can accurately estimate the probabilities in this crap-shoot game of sexual determination.

Meet Tetrahymena thermophila, which in addition to its seven different sexes—conveniently named I, II, III, IV, V, VI, and VII—has such a complex sex life that it requires an extra nucleus. This fuzzy, single-celled critter has a larger macronucleus that takes care of most cellular functions and a smaller micronucleus dedicated to genetic conjugation.

The other odd thing about this one-celled wonder is that the population of the seven sexes are skewed, leading Unversity of Houston researcher Rebecca Zufall and her colleagues to ask: What gives?

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Scientists Look for DNA on Envelopes That Amelia Earhart Licked

By Patrick Morgan | February 22, 2011 2:50 pm

Researchers hope to collect spit from someone who died more than 70 years ago: the aviation pioneer Amelia Earhart. By extracting the famous flyer’s DNA from old envelopes, researchers hope to finally put to rest one of the 20th century’s greatest mysteries.

Earhart disappeared–along with her navigator, Fred Noonan–in 1937, when she was trying to become the first female to fly around the globe. Communication with her plane was lost as she flew near Howland Island in the Pacific Ocean. The U.S. government searched in vain for the two adventurers’ remains, and on January 5, 1939, Earhart was officially pronounced dead. But speculation never stopped on whether the duo died in a crash at sea, or whether they survived for some time on a deserted island.

Just two years ago researchers from the International Group for Historic Aircraft Recovery found bone fragments on Nikumaroro Island that could be part of Amelia Earhart’s finger. The finding is controversial because a dead sea turtle was also found nearby, raising suggestions that the purported piece of Earhart actually belongs to a turtle. According to National Geographic:

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For Fruit Flies, There's Such a Thing as "Too Sexy"

By Patrick Morgan | February 15, 2011 4:02 pm

Beauty doesn’t only fade within a lifetime–it also fades genetically over the course of several generations, according to new research. Scientists studying populations of sexually attractive male fruit flies have found that there’s a limit to their evolutionary success–and that there may actually be a disadvantage to being too sexy.

For the study, published in the Proceedings of the National Academy of Sciences, researchers genetically modified male fruit flies, causing them to give off excessive amounts of attractive pheromones. The scientists then introduced a flock of these foxy fellows to a normal fruit fly population. They discovered that the female flies mated with these modified flies more often initially, and the proportion of super-sexy males increased for a while–but the proportions returned to normal after seven generations.

As The New York Times reports:

“Even though we were able to make males more attractive, there must have been a fitness cost,” said Katrina McGuigan, a biologist at the University of Queensland and one of the study’s authors. “While sexual selection is really powerful, there are consequences to nonsexual traits.”

It’s not yet clear what genetic disadvantage these fruit fly ladykillers may have had. But let’s turn to the more urgent question: Is there any carryover implications for humans? The New York Times quotes McGuigan:

“Hard to say, but only that very attractive individuals may well have something wrong with them — they may not be as good as they seem to be at first glance.”

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Image: Wikimedia Commons / A. O’Toole

I Like Your Genes… Let's Be Friends!

By Patrick Morgan | January 18, 2011 1:41 pm

Whether we’re making them or receiving them, first impressions can have big consequences. Our initial gut feelings transform strangers into potential friends, acquaintances into future partners. And according to some scientists, that initial whiff of personality is tied to genetics.

Looking at data on friendships and genetics from both the National Longitudinal Study of Adolescent Health and the Framingham Heart Study, scientists noticed two trends: people with a genetic variant linked to alcoholism tended to flock together, while those with a genetic variant tied to metabolism and openness to new ideas tended to stay away from each other.

TIME quotes lead researcher James Fowler of the University of California-San Diego:

“This might be the first step towards understanding the biology of ‘chemistry,’ the feeling you have of … whether you like or dislike a person [almost immediately],” Fowler says, noting that this can affect both romantic connections and friendships. “We might choose friends not [only] because of social features we consciously notice but because of biological and even genetic features that we unconsciously notice.”  In turn, the friends we have could then affect the potential partners we meet.

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MORE ABOUT: friendship, genes, genetics

Guilt-Free Procrastination: This Online Game Could Cure Genetic Diseases

By Jennifer Welsh | November 30, 2010 11:02 am

phyloHave a brain for puzzles? What about ones that help advance science?

A new online game called Phylo is harnessing the power of idle brains on the Internet–asking any and all to help align genomic sequences. Human brain power is used instead of computer power because, as the researchers explain in the press release, humans are still better at some things than computers are:

“There are some calculations that the human brain does more efficiently than any computer can, such as recognizing a face,” explained lead researcher Dr. Jérôme Waldispuhl of the School of Computer Science. “Recognizing and sorting the patterns in the human genetic code falls in that category. Our new online game enables players to have fun while contributing to genetic research–players can even choose which genetic disease they want to help decode.”

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"Dance Your PhD" Winner Knows the Molecular Moves

By Eliza Strickland | October 20, 2010 5:10 pm

Have you ever seen an amino acid really get down? If not, now is your chance. The winning video produced for Science‘s Dance Your PhD contest features an amino acid that knows how to shake its molecules. The contest asks brave researchers to explain their PhDs in the language of dance.

This year’s winner is Maureen McKeague, a chemistry Ph.D. student at Carleton University in Ottawa, Canada. She’ll collect a $1,000 prize ($500 for being a finalist, $500 for winning) from Science. With no further ado, here’s the video:

Did you get all that? If a little more explanation would help, here’s how ScienceNOW sums it up:

The lab is exploring a chemical technique called SELEX–systematic evolution of ligands by exponential enrichment–which generates short segments of DNA and RNA called aptamers. These nucleic acids can be designed to stick to almost any target molecule. For McKeague’s Ph.D. research, the target molecule–played by undergraduate student and Scottish folk dancer Charlotte Bradley–is the amino acid homocysteine. High levels of this amino acid are an indicator of cardiovascular disease. McKeague’s aim is to use SELEX to create aptamers to cheaply and accurately measure homocysteine in blood samples.

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CATEGORIZED UNDER: Events
MORE ABOUT: dance, DNA, genetics

To Catch Hamburglars, McDonald's Installs DNA-Spraying Security System

By Eliza Strickland | October 20, 2010 11:49 am

HamburglarA McDonald’s in the Dutch city of Rotterdam has decided to crack down on burglaries with a high-tech security system previously used in the city’s jewelry stores. To catch anyone who makes off with the cash from the till (or a bag of Big Macs), the store’s managers installed a device that stealthily sprays synthetic DNA on the thief.

The system involves a small, strategically placed orange box that shoots out synthetic DNA when an employee pulls an unusual trigger: Removing a €10 bill from a special bill clip behind the counter not only activates the device, it also alerts the police that a robbery is in progress. The synthetic DNA spray is visible under ultraviolet light and contains markers that are unique to that location’s device, allowing police to match a suspect with the locale.

The security-conscious McDonald’s advertises the presence of its system with a sign on the door reading, “You Steal, You’re Marked.” The New York Times explains that the effect of the device is, well, subtle:

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CATEGORIZED UNDER: Crime & Punishment

The Platypus Can Poison You 80 Different Ways

By Jennifer Welsh | October 13, 2010 4:50 pm

platypusThe platypus is a bit like a fruitcake. Shove a bunch of leftover genes in there, mix it up and send it to your relatives see what kind of animal you get.

That’s kind of the approach evolution used when designing this odd creature’s venom; scientists have just determined that the venom contains over 80 different toxins in 13 different classes. The poison can kill small animals, and can leave humans in pain for weeks. The venom is delivered through a barb on the male’s foot–it’s thought that the fellas use the poison during mating season to show dominance.

At least three of the toxins are unique to the platypus and the rest are strikingly similar to proteins from a variety of animals including snakes, lizards, starfish, and sea anemones. It seems that some of these toxins have evolved separately in different animal lineages to perform the same function, a process called convergent evolution. The study‘s lead author, Wesley Warren, told Nature News:

Warren says that this probably happens when genes that perform normal chores, such as blood coagulation, become duplicated independently in different lineages, where they evolve the capacity to carry out other jobs. Animals end up using the same genes as building blocks for venom because only a subset of the proteins the genes encode have the structural and functional properties to become venoms, he adds.

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Does a 200-Year-Old Gourd Contain the Blood of a Beheaded King?

By Jennifer Welsh | October 13, 2010 12:27 pm

louis-xvi-blood-gourd-2-elsDried blood on a handkerchief, a $700,000 gourd and one dead king. A forensic murder mystery?

Nope, just another genetics paper. I mean, it is gourd season, what did you expect?

The dead king in question is Louis XVI (the last of the French kings), who was ceremoniously beheaded on January 21st, 1793. After the beheading, attendees rushed the stage and dipped their handkerchiefs in the royal blood.

Over two hundred years later, some of that blood may have been found–dried to the inside of a decorative gunpowder gourd. The story goes that one of the attendees rushed home and stuffed the bloody handkerchief into the gourd for safekeeping.

In a study published in the journal Forensic Science International: Genetics, researchers analyzed some of the dried blood scraped from the inside of the gourd to find out if it really could be the king’s blood. They checked the Y chromosome to see if the blood-donor was male, and checked for the presence of a blue-eye gene, HERC2. The blood was indeed from the correct time period and belonged to a blue-eyed male–so far, the evidence fits the blue-eyed king. More genetic information about the family will be needed to confirm the identity, the study’s lead author told Wired’s Dave Mosher:

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