Stories tagged genetics
You kids get out of here!: Are those cigarettes? What do you have under that hat? Is that a gang sign?
Courtesy fromagieI’m tired of you hanging around with those riff raff friends of yours. I hear that they smoke. Do you think smoking is cool? Is cancer cool too, then?
And y’all listen to that loud gang music, and I know what that music is about: it’s about devil worship. Devil worship and gangs.
And no son of mine is going to wear eyeliner and dog collars. What do you think you are? A dog? A prostitute? Some kind of prostitute dog?
Didn’t I raise you right, Junior? Where’d all this garbage behavior come from?
And pause!
What’s happening here, folks? Where did Junior’s delinquent behavior come from? Well, I’ll tell you where it came from: it came from his parents, in more ways than one.
Recent genetic research has shown that the tendency of adolescent males to associate with delinquent peers has strong association with a particular variation of the dopamine transporter gene, DAT1. So, basically, there’s a genetic influence behind nogoodniks sticking together.
It’s sort of a disturbing finding, when you consider past efforts to isolate—and eliminate—“unfavorable” genetic traits (it’s called eugenics, and it’s bad, bad news). However, the research also demonstrated that not all males with the DAT1 variation were more inclined to associate with delinquent peers. In fact, a large group of boys with the genetic variation showed no increased tendency towards delinquent peer groups at all: boys with highly engaged and warm families.
Family environment seemed to be the deciding factor in a kid’s chosen social group. Boys most likely to run with a bad crowd had the DAT1 variations and a family life marked by maternal disengagement and lack of affection.
Once again, the answer to “Nature or Nurture?” seems to be, “yes.”
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Cute, nautical, and Scandinavian: But probably smaller.
Courtesy hans sSo… we’re learning about genetics, aren’t we? We can’t help it—here we have see-through frogs, there we have genetically engineered vegetables, here we have a fatherless child with the same hair color, eye color, and blood type as me. Genetics are all around us these days, in our schools, in our dinners, and calling our lawyers. As much as we might try to hide from it, the subject is unavoidable.
It’s nice, then, when some aspect of this genetic tsunami can take our minds off of all the tricky stuff. Things like mutant frogs are fun (All those legs! Somebody give them their own cartoon!), but they never last long (The frogs tend to die. Cancel the frog show.)
I think, however, that I may have found a winner: Viking mice. They’re genetically remarkable, and they’re lifespan is the same as any other mouse: about 2 or 3 years. Somebody start work on a Viking Mouse cartoon!
So what we have here is your common house mouse. The house mouse evolved into a variety of different strains as it spread into Western Europe about 3,000 years ago, during the Iron Age. Little French house mice learned to wear berets and smoke cigarettes, German mice developed a love of sausages and efficiency, and so forth; the Iron Age was a wonderful time, and it birthed many of our favorite cultural stereotypes. However, something interesting has come up in a recent genetic study of British house mice.
The surprising result of a nationwide rash of mouse paternity cases, the mice of Britain were surprised to find that they themselves were the products of unexpected parents. Studying their mitochondrial DNA (traceable genetic material from the mother’s side), it appears that most mice from mainland Britain are closely related to mice from Germany (the descendants of little Saxon mice?). Mice from the Orkney Islands of Northern Scotland, however, were found to be “Viking mice,” genetically similar to mice from Norway. And it makes sense—the Orkneys were an important center of the Norwegian Viking “kingdom,” back in the 11th and 12th centuries. These little mousies are the descendants of the warlike Viking mice, who hitched rides across the North Sea in the holds of Viking longboats a thousand years ago. Or… maybe they had their own tiny boats… Viking mice!
We pretty much already knew that Vikings were in the Orkneys at that time, but the genetic evidence from the mice are is a good example of how non-human DNA (mitochondrial DNA in particular) can be a tool for tracking other historical human migrations, and… and…
Just picture those little Viking mice. Tiny helmets, curly little beards, squeaky battle cries… they must have been adorable. Just to see them slaughtering little monk mice, it must have been too cute.
Oh, also, while we’re on the subject of house mice—I noticed this little section in Wikipedia’s article on them. After being accidentally introduced to the south Atlantic Gough Island, house mice, which normally have a body length of about 3 inches, began growing “unusually large” and feeding on albatross chicks. The mice kill the chicks, which can be about a meter tall, by “working in groups and gnawing on them until the bleed to death.” Talk about Viking mice.
Six-toed cats can remain at Hemingway museum
in Life Science, Diversity of Organisms, and Biological Populations Change Over Time
Hemingway cat: One of Snowball's many descendants takes it easy behind the Hemingway Home and Museum in Key West, Florida.
Courtesy Mark RyanThe fifty or so cats living around the former estate of author Ernest Hemingway in Key West, Florida, have been granted a reprieve from the US Department of Agriculture and are being allowed to remain on the grounds where the famed novelist once lived. The island property is now the Hemingway Home and Museum, and one of Key West’s more popular attractions. The federal agency originally wanted the cats removed or caged because the museum lacked the proper license to exhibit animals.
All the cats roaming the grounds are descended from a cat named Snowball given to the author by a ship’s captain in the 1930s. Snowball was a polydactyl cat, meaning its paws contained more than the usual number of toes. Typically a cat has 18 toes – five on the front and four on back. Polydactyls commonly have six or seven toes on the front, and sometimes an extra one on the rear, but the record is held by a California cat that had an incredible eight toes on each foot! Polydactyly is a congenital abnormality genetically passed down to offspring. In some cases the extra toes are like opposable thumbs giving the cats an almost human-like dexterity. Snowball’s descendents all carry the genetic trait but not all are polydactyl.
Ernie the cat
Courtesy Mark RyanOur family cat was a polydactyl, and we named him Ernie in honor of Hemingway and his six-toed cats. Ernie’s extra-large feet allowed him to gain lots of weight during his life with us. At his heftiest he weighed 24 pounds. He was huge, a real lard butt. His full name - Ernesto ”El Gato Gordo” Hemingway - was well deserved.
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 HealthRecord 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.
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 foreversoulsRemember 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?
Climate. It gets in your blood.
in Diversity of Organisms, Heredity, Biological Populations Change Over Time, and Human Organism
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.
Can you spot the nightmare?: There he is!
Courtesy FasterDixOkay. 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.
Welcome to the future: The apples are different here.
Courtesy t.shirbertWho 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.
Chickens may hold secret to human allergies: Does this cause a bad reaction?
Courtesy foxxyzThis spring, for the first time in my life, I suffered from seasonal allergies. Not a terrible case of them, but it wasn't pleasant, and who knows what the future holds for me. Fortunately, a new study in the Journal of Biological Chemistry tells of the pinpointing of a "fossilized" molecule found in chickens that opens a new avenue of study of why humans develop severe allergic reactions. The chicken molecule, named IgY, appears to be ancestral to the IgE molecule found in humans that binds to white blood cells and causes the human immune system to overreact. This means the evolution of allergic reaction can now be traced back to at least 160 million years.
Scientists witness evolution in lab
in Cells, Heredity, Biological Populations Change Over Time, and Flow of Matter and Energy
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.
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