Friday, July 11, 2014

Proof that Boys Better Behave Because It Looks Like Evolution Is Playing On The Girl's Team!

No Sex Needed: All-Female Lizard Species Cross Their Chromosomes to Make Babies

These southwestern lizards' asexual reproduction is no longer a secret

asexual lizard
Since the 1960s scientists have known that some species of whiptail lizards need a male even less than a fish needs a bicycle. These all-lady lizard species (of the Aspidoscelis genus) from Mexico and the U.S. Southwest manage to produce well-bred offspring without the aid of male fertilization.

But how do they—and the other 70 species of vertebrates that propagate this way—do it without the genetic monotony and disease vulnerability that often results from asexual reproduction? "It has remained unclear" and "has been the topic of much speculation," report a team of researchers who aimed to answer just that question. Their results were published online February 21 in the journal Nature. (Scientific American is part of Nature Publishing Group.)

These lizards and other "parthenogenetic species are genetically isolated," explains Peter Baumann, an associate investigator at the Stowers Institute for Medical Research in Kansas City, Mo., and co-author of the study. Species as diverse as Komodo dragons and hammerhead sharks do it asexually if necessary, but some species, like these little lizards, don't have a choice. "They can't exchange genetic material, and this loss of genetic exchange is a major disadvantage to them in a changing environment," he says. Unless an animal can recombine the DNA they already have, they will produce an offspring with an identical set of chromosomes, in which any genetic weakness, such as disease susceptibility or physical mutation, would have no chance to be overridden by outside genetic material from a mate.

The new research by Baumann and his team reveal that these lizards maintain genetic richness by starting the reproductive process with twice the number of chromosomes as their sexually reproducing cousins. These celibate species resulted from the hybridization of different sexual species, a process that instills the parthenogenetic lizards with a great amount of genetic diversity at the outset. And the researchers found that these species could maintain the diversity by never pairing their homologous chromosomes (as sexual species do by taking one set of chromosomes from each parent) but rather by combining their sister chromosomes instead. "Recombination between pairs of sister chromosomes maintains heterozygosity" throughout the chromosome, noted the authors of the study, which was led by Aracely Lutes, a postdoctoral researcher in Baumann's lab.

This discovery, which had until now been unconfirmed in the reptile world, means that "these lizards have a way of distinguishing sister from homologous chromosomes," Baumann says. How do they do it? That's something the group is now investigating.

Another big unknown is precisely how the lizards end up with double the amount of chromosomes in the first place. Baumann suspects that it could happen over two rounds of replication or if two sex cells combine forces before the division process starts.

Although asexual reproduction might seem like a bore—and one that can have questionable genetic outcomes unless done right—it has its benefits, too, Baumann notes. "You're greatly increasing the chances of populating a new habitat if it only takes one individual," he says, citing the example of the brahminy blind snake (Ramphotyphlops braminus), another parthenogenetic species. "If she has a way of reproducing without the help of a male, that's an extreme advantage." Indeed it is—the brahminy has already colonized six continents.


Edgar Mitchell Is Now My Favorite Astronaut

 People magazine, 8 April 1974.

Sunday, July 6, 2014

Samantha Keely Smith

Had I the Heavens’ embroidered cloths,

Enwrought with golden and silver light,

The blue and the dim and the dark cloths

Of night and light and the half light,

I would spread the cloths under your feet.

But I, being poor, have only my dreams.

I have spread my dreams under your feet,

Tread softly because you tread on my dreams.

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Wednesday, June 18, 2014

‘Savage Beauty’ Alexander McQueen

I was weary of couture. There were artists to be sure, but the runways of Fashion Week had more and more become flooded with a lot of hype and nothing really interesting or new to say. I felt jaded and bored by the endless parade of 'shocking' silhouettes that often had nothing whatever to do with the human forms they rested upon. I just didn't believe anything could be great anymore- until I saw Alexander McQueen.

He electrified my senses with his materials, themes, artistry and overwhelming beauty. When I was lucky enough to hold some of his pieces in my hands, I was in total awe of the exacting and elegant craftsmanship that allowed the garments to take on their own life.

My heart was broken the day I found out he took his own life. I selfishly wanted him to continue to surprise, challenge and delight me (and the world) for ever and ever.