Stories tagged genetics

Feb
08
2008

Blue for you: Danish researchers have concluded that the genetic trait that leads to blue eyes comes from the mutation of one gene some 6,000 to 10,000 years ago.
Blue for you: Danish researchers have concluded that the genetic trait that leads to blue eyes comes from the mutation of one gene some 6,000 to 10,000 years ago.Courtesy wikipedia
Do you have blue eyes? If yes, you’re genetically connected to Paul Newman, Brad Pitt and Gwyneth Paltrow according to the findings of a new study.

Researchers in Denmark have announced their finding that all people with blue eyes have a single, common ancestor. Their theory is that a genetic mutation occurred 6,000 to 10,000 years ago that was the beginning of the blue-eyed phenomenon.

Through their study, all humans at first had brown eyes. A mutation created an on/off switch in a specific gene controlling eye color of humans. When triggered to switch off, it stopped the body’s ability to make brown eyes, researchers say. More scientifically, the off switch reduces the body’s ability to create melanin in the iris of the eye. With less melanin, brown eye coloring is diluted to blue.

It’s a very specific mix of genetic code that leads to blue eyes, the researchers continue, while there is much diversity in the genetic make-up of brown- or green-eyed individuals.

The best way to think of it, the researchers add, is that our genetic make-up is like a deck of shuffling cards. The traits from our genes recombine in various forms to impact things like hair color, baldness, freckles and beauty spots. Those changes don’t have a huge impact on the survival of their carriers.

Feb
05
2008

Hetero, homo, and 3-way embryo creation

Embryo - 5 weeks
Embryo - 5 weeksCourtesy Ed Uthman
Lesbian couples could one day have children who share both their genes. Karim Nayernia, Professor of Stem Cell Biology at Newcastle University, has applied for ethical approval from the university to use bone marrow stem cells from women to start experiments to derive female sperm.

“I think, in principle, it will be scientifically possible,” Prof Nayernia told New Scientist.

Babies from two men

Other research is setting the stage for a gay man to donate skin cells that could be used to make eggs, which could then be fertilized by his partner’s sperm. A surrogate's uterus would be needed to bring the baby to term.

In Brazil, a team led by Dr Irina Kerkis of the Butantan Institute in Saõ Paulo claims to have made both sperm and eggs from cultures of male mouse embryonic stem cells in the journal Cloning and Stem Cells.

Babies from a man and two women

A whole class of hereditary diseases, including some forms of epilepsy, result from faulty DNA related to mitochondria. Starting with 10 severely abnormal embryos left over from traditional fertility treatment, researchers removed the nucleus, containing DNA from the mother and father, from the embryo, and implanted it into a donor egg whose DNA had been largely removed. The only genetic information remaining from the donor egg was the tiny bit that controls production of mitochondria. The embryos then began to develop normally, but were destroyed within six days.

"We believe that from this work, and work we have done on other animals that in principle we could develop this technique and offer treatment in the forseeable future that will give families some hope of avoiding passing these diseases to their children." said Patrick Chinnery, a member of the Newcastle team.

If you have an opinion on these types of research, feel free to comment.

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Jan
21
2008

Carrots
CarrotsCourtesy niznoz
Researchers at Texas A&M and Baylor College of Medicine have genetically engineered a carrot that could deliver up to 40% more calcium. These scientists hope to start genetically modifying foods to increase their nutritional value. The genetic engineering of food so far has focused mostly on keeping crops healthy, making them resistant to pests and disease, and increasing their size and productivity. This is all great for farmers but doesn't specifically help you when you eat the food.

Would you be more likely to eat genetically modified foods if they were actually healthier for you? Take the poll.

A new study finds that obesity and over-eating may be caused by the lack of one single gene. (Though there are certainly other causes as well.)

Seems like only yesterday the government was forking over billions of dollars to sequence the human genome. Today, anybody can have their personal DNA sequenced for about $1,000. Previously, doctors would test a patient’s DNA only for a few specific genes that might be related to their condition. Now, perfectly healthy people can have their entire DNA tested (well, about 1/3,000th of it, anyway), to look for all known genetic conditions.

Nov
27
2007

Would have cancer killed Lincoln?: An author/physician theorizes that Abraham Lincoln would have soon died from a rare form of cancer if he had not been assassinated at Ford's Theater in 1865.
Would have cancer killed Lincoln?: An author/physician theorizes that Abraham Lincoln would have soon died from a rare form of cancer if he had not been assassinated at Ford's Theater in 1865.Courtesy Civics Online
I just finished reading an incredible book about Abraham Lincoln – Team of Rivals: The Political Genius of Abraham Lincoln -- by Doris Kearns Godwin. Of course, it ends with his assassination at Ford’s Theater right after the end of the Civil War.

Much to my surprise today, I come across a headline that at the time of his death, Lincoln may have only had about six months to live due to the effects of a rare type of cancer. Doctor/author John G. Sotos makes the case for Lincoln’s cancer diagnosis in an upcoming book.

One thing that struck me in Team of Rivals, which is written based on thousands of letters and diaries written by Lincoln’s associates during the time he was alive, was that most were first impressed and/or put off by his unusual appearance. Sotos theorizes that those appearances were related to Lincoln’s cancer.

Sotos thinks Lincoln suffered from MEN 2B, a genetic form of cancer that can account for unusual height along with unusual facial features – lumps of nervous tissue on the eyelids, tongue and lips. Sotos also thinks one of Lincoln’s sons died from the same type of cancer

And CSI-type techniques may come into play to see if Sotos is right. A small sampling of DNA is all that ‘s needed to check the condition of chromosome 10 of Lincoln’s genetic code to see if it shows signs of MEN 2B. Samples of his DNA can be collected from any of the many blood-stained fabrics that have been preserved from Lincoln’s death, or from the eight skull fragments that were preserved from the president’s autopsy.

If it is determined that Lincoln had MEN 2B, he’d be the earliest recorded case of that type of cancer. But as news of this theory has spread, there are already other members of the medical community saying that it isn’t possible.

What do you think? Should efforts be made to test some of Lincoln’s remains for MEN 2B? Or should we leave the remains alone and keep it a mystery? Share your thoughts here with other Science Buzz readers.

If you want to learn more about this, here’s the link to an extensive Washington Post article on the topic.

Nov
04
2007

A Basking Shark: Just... basking?  (image courtesy of Wikimedia Commons)
A Basking Shark: Just... basking? (image courtesy of Wikimedia Commons)
I gots monsters on the brain!

The Loch Ness Monster (or possibly elephant) has been a pretty hot topic around Science Buzz lately, so this article caught my eye.

A Scottish geneticist is reported to have been researching the "Orkney Beast” (also known as the Stronsay Beast), and will be comparing it to the Loch Ness Monster in a talk she will be giving at the Highlands Science Festival this week.

The Orkney Beast was this huge, bizarre carcass that washed up on the shore of Stronsay, in the Orkney Islands, in 1808. It was pretty rotten at the time, but everybody seemed to agree that it was some sort of sea serpent (it was 55 feet long, with a 15 foot “neck,” and measured 10 feet around). However, a couple of anatomists later decided that it was probably a shark, specifically a large basking shark. The locals were pretty disappointed with this, but who can argue with an anatomist?The Orkney/Stronsay Beast: A drawing of the carcass, made in 1808.  (image courtesy of Wikimedia Commons)
The Orkney/Stronsay Beast: A drawing of the carcass, made in 1808. (image courtesy of Wikimedia Commons)

Even if it was a shark, the Orkney Beast remains an interesting find. The largest basking shark (which is a filter feeder, and the second largest shark after the whale shark) ever recorded was 40 feet, significantly smaller than the beast’s 55 feet.

The skull and “paw” of the creature were sent to London in the 19th century, but were destroyed in World War II. Some remains still exist at Edinburgh’s Royal Museum, however, and the geneticist was given the chance to study them. The article didn’t say what the researcher made of them.

I don’t know that the geneticist is claiming that Nessie or the Orkney Beast are genuine monsters (what a strange phrase), but she points out that the drawings and descriptions made of the carcass at Orkney are strikingly similar to descriptions in “eyewitness accounts” of Nessie. It’s an interesting coincidence, although I suppose people often see what they want to see, even when looking at giant, rotting fish.

Also, this is kind of interesting. Apparently there’s no shortage of Scottish loch monsters.

Update, 7/7/14: JGordon here, 7 years later. 7 years! And to think that my own mother suggested that I'd be comatose, in jail, or comatose and in jail by now. I sure showed her, because I am none of those things! Anyhow, I've updated/edited this post to remove the name of the researcher supposedly associated with the genetic study. Apparently media reporting on this story (me?A) were a little overenthusiastic when it came to describing the scientist's involvement with the tests (which, it turns out, were to be done by a lab in the USA, and didn't happen in any case.) So if you came here looking for info on this scientist, you're barking up the wrong tree; his or her research and education is probably not summed up very well by a cryptozoological story from seven years ago.
JGordon out. See you in 2021.

Sep
16
2007

It's like a big angel food cake, running right at you: If you've got the right combination of genes.  (photo by castle79 on flickr.com)
It's like a big angel food cake, running right at you: If you've got the right combination of genes. (photo by castle79 on flickr.com)
Picture a big mug of some hot, vanilla flavored beverage. Think about how it smells…
Now do the same for a big, hot mug of urine. Now hold that thought.

Androstenone is a testosterone derivative produced in our bodies, and found in our urine and sweat. It is partially responsible for the less than charming smell of these fluids, as it smells like, well, urine and b.o. But it only smells like urine and b.o. to some people – to others it smells a lot like vanilla, and to others still, it smells like nothing at all.

Recently, scientists think they have isolated the gene that determines how people perceive the odor of androstenone. A group of four hundred people were presented with 66 different odors at two concentrations, and asked to evaluate the pleasantness and intensity of each odor. Blood samples were then taken from each participant for genetic testing. The study found that whether a person found androstenone foul or pleasant depended on the combination of “two point mutations called single nucleotide polymorphisms” along a particular odorant receptor gene. Isn’t that something? So, whether a junior high locker room smells like a bakery or an adolescent nightmare all depends the luck of the genetic draw (although I’m not sure that either option is all that great).

Some mammals use androstenone to pass on social and sexual messages. It’s possible that it played some similar role in humans, although, if this is the case, scientists can’t explain why so many people simply lack the ability to smell androstenone at all.

A fun fact: males produce much more androstenone than females. Sorry ladies, but there are some things that we men just do better than you, like producing really stinky chemicals.

Sep
15
2007

Start with this: Japanese scientists have taken a salmon similar to this, injected it with rainbow trout sprem-producing cells…
Start with this: Japanese scientists have taken a salmon similar to this, injected it with rainbow trout sprem-producing cells…
This might sound like something out of Jurassic Park, but Japanese fish researchers have successfully made the first step in artificially boosting low numbers of fish populations.

Through the use of what they call “surrogate broodstocking,” they’ve used salmon to breed rainbow trout. The process injects the sperm-growing cells of rainbow trout into newly hatched Asian masu salmon.

End up with this: a biologically correct rainbow trout that is able to reproduce. (Photos courtesy of the U.S. Fish and Wildlife Service)
End up with this: a biologically correct rainbow trout that is able to reproduce. (Photos courtesy of the U.S. Fish and Wildlife Service)
If that’s not creepy or weird enough for you, check out this. The process has also worked with injecting the male cells into female salmon, who then have ovulated rainbow trout eggs. The offspring are “pure” trout and are able to reproduce offspring that genetically match the trout species.

The ultimate goal by the Japanese researchers is to replicate these efforts to be able to boost the low numbers of bluefin tuna. The research will turn to the U.S. next month in Idaho where the process will be reversed, using the plentiful trout population to be surrogates for creating the ever-increasingly rare sockeye salmon population.

What do you think? Is this tinkering too much with nature? Or is this just the technological gimmick we can use to help adjust the balance of nature our technologies of the past have thrown so far out of whack? Share your thoughts here with other Science Buzz readers.