Stories tagged genetics

Sep
22
2008

What to know and when to know it: Two mammography images show the difference between a non-cancerous (left) and cancerous (right) breast.
What to know and when to know it: Two mammography images show the difference between a non-cancerous (left) and cancerous (right) breast.Courtesy National Institutes of Health
Record numbers of women are opting for a test that checks if their genetic make-up makes them stronger candidates for breast cancer. Last year about 100,000 women were tested. Doctors generally recommend against testing anyone under the age of 25, the same age that mammograms are first recommended. That’s because little can be done to screen or prevent breast cancer before that age.

But a growing movement among young women wants to find out how their genetic make-up could impact their risk for breast cancer. And they want to find out that news at an earlier age.

It’s a hot ethical question in clinics across the country today, which is explained in full detail here.

On the one side, pro-testing people point out that young people armed with this information could make lifestyle choices that could reduce their cancer risk. There is some evidence that young women with a positive genetic test have quit smoking, for example. Others have limited alcohol intake or avoided using birth control pills, two other factors that can raise breast cancer risk.

On the other side of the debate, researchers say that young women have enough health issues to deal with at an early age. Ringing alarms for something they can’t be “officially” tested for until later in life is just one more worry that they really don’t need to deal with at the time.

The tests themselves cost around $3,000. More and more medical insurance companies are providing coverage for the test.

If the test shows a faulty gene, the patient’s risk of developing breast cancer is three to seven times higher. In a few cases, parents have tested the genes of their pre-adolescent children. One girl test was just four years old.

What do you think? Is this good genetic curiosity or being a genetic busy-body? Is it important to find out this information if nothing can be done to treat the situation for a number of years? Share your thoughts here with other Buzz readers.

Jul
17
2008

Mmmm, mmmm good: Is there anything better than a summer day and a slice of watermelon? I'll take my watermelon with seeds or without; I'm not picky.
Mmmm, mmmm good: Is there anything better than a summer day and a slice of watermelon? I'll take my watermelon with seeds or without; I'm not picky.Courtesy foreversouls
Remember the good old days of summer when you could chomp on a slice of watermelon and spit out the seeds? Those Tom Sawyer moments are getting far and few between with the growing popularity of seedless watermelon. In fact, when you go to the store, it’s hard to find a watermelon these days with the conventional hard, black seeds.

How can a watermelon grow without seeds?

Seedless watermelons have been around for more than 50 years. And while they’re called “seedless,” they actually do have small white seeds in them. What they don’t have are the large, hard black seeds that no one wants to swallow. So how do they grow? It all boils down to the chromosome level. Chromosomes are the genetic building blocks in all living things that give them their physical traits.

Watermelon breeders have discovered that if you cross breed a watermelon with two sets of chromosomes with one that has four sets of chromosomes, you end up with a melon with three sets of chromosomes. That’s called a triploid seed, and when planted, it produces a watermelon that produces small seeds that won’t reproduce. It’s the plant world equivalent of a crossing a horse and a donkey to get a non-reproducing mule. Here's a link to an NPR report about how seedless watermelons, and other seedless fruits, are developed.

While consumers have expressed their strong preference for seedless watermelons, that hasn’t put the seeded varieties out to pasture, so to speak. Seeded watermelons still play a crucial role in the production of seedless watermelons.

Along with the crossbreeding work that’s needed to create seedless watermelon seeds, seeded watermelons need to be planted among seedless watermelons for their fruit to develop properly. A field producing seedless melons will have around 25 percent of its plants being seeded melons to help in the pollination process. Bees cross pollinate between the two plants. Without that cross pollination, the inner fruit of the watermelon will not develop.

And no one would want that, now, would we?

Jul
06
2008

Or at least your genes. A new study has found that men in Arab countries carry two different versions of a gene set called “Haplogroup J.” Those with one set come from wetter lands, and are descended from farmers. Those with the other set come from drier lands, and are descended from herders. Scientists speculate that climate change in the Middle East some 11,000 years ago split the population in two. As lands grew drier, some people were still able to farm, but others had to give up the farm and turned to sheep herding and similar pursuits. The two groups didn’t mix much thereafter, and eventually evolved slightly different genes.

The division of the population into two groups also affected material culture, such as the pottery each produced; lifestyle; and possibly even religion.

Jul
03
2008

Can you spot the nightmare?: There he is!
Can you spot the nightmare?: There he is!Courtesy FasterDix
Okay. Now I know what you’re thinking: “Every scene in Willow is frightening. Each scene is, in fact, somehow the most frightening scene. Will all of that become real too?”

Don’t worry, my doves, don’t worry.

You won’t be pursued through the forest by horrible pig dogs.

You won’t be puked on by a magic baby.

Your ethnicity won’t be slandered by drunks and soldiers.

You will not be captured and molested by hideous little rat men.

Monkeylike trolls will not chase you through derelict castles.

You won’t have to watch one of those awful trolls turn inside out and morph into a dragon. And you will not have to fight that dragon.

A shirtless Val Kilmer will not threaten you.

There will not be epic battles, nor attempted baby sacrifices.

You will not be stabbed by a man with a skull mask and an unspeakable caveman face.

A metal brazier will not chase you around a lightning-lit tower.

No wands will be brandished at you.

The town loudmouth will not belittle you in front of your family.

So, all in all, there’s relatively little to be concerned about. That said, there is one more most frightening scene to consider.

Do you remember when the army of Madmartigan and Airk Thaughbaer first laid siege to the fortress of Nockmark? Before Willow was able to fully control the powers of Cherlindrea’s wand and return Fin Raziel to her human, albeit greatly aged, form? You’ll recall that as soon as Airk, Madmartigan and Sorsha confront Bavmorda at the gates of Nockmark, the evil enchantress turns the whole of the attacking army into pigs. Once they were pigs things don’t seem so bad, but the process of turning into pigs was horrible to watch. There were hoof-hands everywhere, and emerging piggy snouts, and tusks, and oinking, and everybody looked really sweaty. It was very frightening to see, and it’s happening in our own plane of existence: human-pig hybrids have been given the go-ahead in England.

Careful examination of the story clearly indicates that half human, half pig creatures like those in Willow are neither the intent here, nor are they actually possible from these experiments. But I tend to believe what I imagine is the case more than what I’m old is the case.

If you do want to waste your time with what you’re told, however, listen up:
The aim of this research is in no way to create a weird pig man. Or a weird man pig. The goal is actually to put human DNA from skin cells into a pig egg that has had its chromosomes removed, and then let it develop into an embryo. In fact, the scientists involved are attempting to create an embryo with no animal DNA left in it at all (kind of ironic, I suppose).

There’s more to it, of course, but the idea is this: the human DNA put into the eggs will be DNA taken from people with a genetic heart disease. As the scientists observe the transformation from egg to embryo, they hope to better understand the molecular mechanics of the disease. That information could then be used to create better treatments for people living with related heart conditions. None of the “hybrids” will develop past the very first stages of being an embryo (basically a featureless sphere of cells).

Or, if you’re into letting your gut and imagination do your critical thinking for you…prepare yourself for Island of Doctor Moreau Earth.

Jun
24
2008

Welcome to the future: The apples are different here.
Welcome to the future: The apples are different here.Courtesy t.shirbert
Who else is tired of boring old apples? C’mon, everyone, you know you know it. I know you know it. Just say it: I’m tired of boring ol’, unsurprising, jive-axe, apples. Let it out. It’ll feel so good: all these apples taste like apples—if I wanted to eat a clone, I’d tear apart a lamb, not an apple. Am I right? Don’t answer that—I know I’m right.

Fortunately for us, we brave surfers of the future, at least one scientist has joined our army of edgy discontent.

Apple trees, it just so happens, don’t produce apple seeds that are exactly like themselves. Why would they? Humans never produce children exactly like themselves, and that sort of genetic variation suits us well. But if there were a particular human that tasted tart and crisp and delicious, wouldn’t we want that person’s offspring to be exactly the same? Maybe. With apples, at least, that has certainly been the case.

So, to ensure that the varieties of apples we’re so familiar with keep their desired characteristics, commercial apple trees are always propagated by grafting a chunk from an existing tree onto sturdy rootstock. That way you get a new tree identical to the old one, and you get the lame Junior Crisp, Granny Spice, and Yellow Fantastic apples that we’re all tired to death of.

The apple science of the new millennium, however, is looking past this past of homogeneity. While some catalogued and selected-for traits, like resistance to certain diseases, are worthwhile retaining, some geneticists are exploring the potential of increased variation. Apple trees at Cornell University have been made to grow in columns, instead of branching out at their crowns, and to produce fruit while remaining the size of a shrub, or to have weeping branches like willow trees. Similar variability can be found in the fruit itself—flavors like “anise, berries, or roses” exist, and fruit with as much vitamin C as an orange, or one that is loaded with antioxidants, have been envisioned. How about that?

Buzzketeers, put on your worker hats and Che t-shirts, and throw out your old apples. It’s revolution time.

Man. What was the point of this post? Oh, yeah—work is being done on genetically engineering apples to have different, interesting characteristics. Brave new world, crazy apples.

Jun
20
2008

For decades, scientists have been growing microbes in their labs and watching them evolve new traits. Most of the changes tend to be simple things, like an increase in size or growth rate.

But Dr. Richard Lenski of Michigan State University (just 2 miles from my house!) recently witnessed a major evolutionary leap--as it was happening. Twenty years ago, he took a colony of E. coli, a common bacteria, and split it into 12 identical populations. He’s been watching ever since to see if the strains evolve in different directions.

A few years ago, one of them did. One of his study strains suddenly evolved the ability to eat citrate, a molecule found in citrus fruits. No other E. coli in the world can do this, not even the other strains in Dr. Lenski’s lab. Even given several extra years and thousands of extra generations, the other strains are still citrate-averse. What’s more, the bacteria evolved this mutation entirely on their own, without any prodding or genetic manipulation from the researchers.

Lenski had saved frozen reference samples of all of his strains at regular intervals. Going back and growing new cultures from these samples, he again finds that only those from one strain ever evolve the citrate-eating habit – and only those sample less than about 10 years old. Lenski figures that some mutation happened around that time in one strain – and one strain only – that would later lead to citrate eating. He and his lab are now working on figuring out exactly what that mutation is.

May
29
2008

When your old Viking wears out: Just toss him out and buy a fresh one.
When your old Viking wears out: Just toss him out and buy a fresh one.Courtesy Extra Medium
We live in exciting times. If I knew how to spell “exciting” I would write it out, letter by letter, just to emphasize how exciting these times are. E X I T I N G.

F A Y L Y U R.

Who among us hasn’t sat at home as a child, listening to Wagner, wishing that Vikings still existed, or even, perhaps, that we might have our own little Viking…

But farewell my little Viking—thems is dreams, just dreams.

Or are thems? Is thems?

The Danes, you see, have had their scientists hard at work, scouring the earth for viable Viking DNA. Their first thought was to mine archaeological sites for petrified Viking beard dreadlocks, with the hope that somewhere inside might be preserved ticks, full of rich Viking blood. This idea was quickly abandoned, however, on account of its being “indskrænket.”

The geneticists then considered a much simpler solution: getting dirty in a Viking grave. Using teeth from a thousand year old Viking burial on the Danish Island of Funen, the scientists were able to obtain “authentic Viking DNA!”

The world is changing! Can you feel it? It’s like sitting in a warming hot tub!

Soon we will be able to observe real cloned Vikings! Just think…we’ll finally know if their helmets really were horny…we could even have a Viking theme park on an island (I’m thinking Funen). I think it could work!

Real Vikings…

Some might argue that the point of this research had nothing at all to do with cloning Vikings, or cloning at all. They would probably point out that retrieving ancient human DNA is notoriously fraught with complications involving modern genetic contamination, as well as simply finding fully intact DNA molecules (fill the gaps in the Viking DNA with frog genes. Duh). They might also say that analyzing ancient DNA can tell us about the origins of diseases, human migration patterns, and tribal and family organizations not recorded by history.

Yawn. Wake me up when they mention “pet Viking.”

The Danish researchers collected and analyzed the DNA in meticulously controlled situations, wearing full body suits and facemasks during collection and using sterilized tubes for transport of the specimens back to the lab. A wise move, I think—if the samples were contaminated, just think about the monstrosity that could emerge from the cloning procedure that is sure to come: a Viking/Danish hybrid. It would be like The Fly, I bet.

And speaking of mud, scientists in Europe are experimenting with the genes of a light-sensitive algae, in hopes that they can be used to treat certain types of blindness.

Okay, so this has a bit of a freak show feel to it, but here's some National Geographic video of a baby recently born in India that has two faces. It's not a conjoined twin, because it has just one torso. Interestingly, the parents do not want to have MRIs done the baby to see if there are any abnormalities inside her body.

Feb
17
2008

Nearly identical twins: The difference being, of course, that the boy on the left thinks only evil thoughts.
Nearly identical twins: The difference being, of course, that the boy on the left thinks only evil thoughts.Courtesy Chubby Bat
Genetic studies have recently revealed that identical twins are only mostly identical.

Identical twins, by definition, should have the very same DNA. While the genome is virtually identical, says a report in the American Journal of Human Genetics, there are tiny and fairly common differences in the genetic makeup of twins.

Each set of twins involved in the study had the same DNA, but “evinced differences in the number of copies of individual DNA segments.” So some twins could have multiple copies of a segment of DNA, while their siblings might be missing the same segment altogether.

The study complicates our view of genetics, but might lead to a better understanding of why identical twins sometimes have significant differences in health. Parkinson’s disease, for instance, can develop in one twin and not the other, and until now environmental factors were thought to be the only explanation for that sort of thing.

What’s most remarkable about the study, to me at least, is that these geneticists claim to have discovered something that I learned from watching a video when I was seven. I am, of course, referring to the 1988 documentary Twins. The film follows two separated-at-birth twins, within whom a keen observer can detect subtle discrepancies in morphological phenotypes. One of the brothers, Julius, looks strikingly like a younger version of California’s governor, while the other brother, Vincent, looks a little more like some kind of goblin, possibly a gnome. Also, Vincent has latent criminal tendencies, and Julius is cursed with deeply sub-average intelligence. So while this study sheds a certain amount of light on the subjects of the film, I’m not sure that the scientists should go around talking about “original research.” At the very least, I hope that Ivan Reitman is credited in their bibliography.