- Short Story Collections Not To Be Missed This Summer
- Short Story Collections Not To Be Missed This Summer
- Short Stories: Journeys - PopMatters
- 1. The Refugees by Viet Thanh Nguyen: £12.99, Little, Brown
The view, according to these genomic explorers, is no less than awe-inspiring! In other areas, genes are spread over the vast expanses like farmhouses on the prairie. And then there are large tracts of desert, where only non-coding 'junk DNA' can be found.http://www.cantinesanpancrazio.it/components/jometexid/352-come-recuperare-messaggi.php
Short Story Collections Not To Be Missed This Summer
Each region tells a unique story about the history of our species and what makes us tick. This landscape contrasts starkly with the genomes of many other organisms, such as the mustard weed, the worm, and the fly. Their genomes more closely resemble uniform, sprawling suburbs, with genes relatively evenly spaced along chromosomes. The human genome's gene-dense urban centers are predominantly composed of the DNA building blocks G and C and are called "GC-rich regions.
GC- and AT-rich regions can actually be seen through a microscope as light and dark bands on chromosomes.
- Wild, Wild, Wives (Roxanne)?
- Belmont und Constanze: Die Opern der Welt (German Edition);
- Local by Brian Wood.
On each human chromosome, there are large and noticeable swings in GC content; one stretch might have 60 percent while an adjacent stretch might have only 30 percent. These swings could never occur randomly and represent a definite organization of "neighborhoods" with local accents. The urban centers contain a ten-fold higher density of genes than the deserts. Another interesting feature is that so-called "HOX gene clusters," which play an important role in development, are never invaded by junk DNA. This suggests that evolution has a reason for retaining the integrity of these gene clusters.
Near the gene cities are neighboring regions of the dinucleotide CpG - stretches of up to 30, letters with only two bases, C and G, repeating over and over. Usually underrepresented throughout the genome, many CpG regions help regulate gene function. Predictions regarding the number of genes in the human genome have been as variable as the biotech index in the NASDAQ, with estimates ranging anywhere from 20, to , genes.
Ending this decade-long period of wild speculation, the international consortium now reports that they have arrived at a more accurate and stable estimate. They have concluded that the genome contains between 30, and 35, genes. Although small gaps in the human genome sequence must be filled before scientists can arrive at an exact number, they now have almost all of the data they need to make an accurate projection.
This news represents a humbling reality check for those who have long harbored hubris about the number of genes in humans. The new estimate indicates that humans have only twice as many genes as the worm or the fly! How can human complexity be explained by a genome with such a paucity of genes? It turns out humans are very thrifty with their genes, able to do more with what they have than other species.
Instead of producing only one protein per gene, human genes can produce several different proteins. Humans use a process called "alternative splicing," in which different parts of a protein can be rearranged as needed-much like parts of tinker toys-to make different proteins from the same basic components.
Alternative splicing is possible because human genes are spread out over large regions of genomic DNA, and regions that code for proteins are not necessarily continuous, allowing one gene to code for different parts of a protein. On the average, each human gene probably makes three proteins, more than worms and flies do. Because genes comprise a tiny fraction of the human genome, they are the most challenging to identify in the genome sequence.
Thus, the predicted genes and protein sets described by scientists are not final; they will continue to be fine-tuned as better gene-finding tools are developed. The low number of genes comes as good news for scientists in academia and pharmaceutical companies. Gene hunters who want to compile a compendium of all genes, and pharmaceutical companies looking for finite numbers of drug targets, have just had their work, time, and expense cut significantly. Why reinvent the wheel when you've got a strategy that works? Evolution certainly seems to operate that way, especially where human proteins are concerned.
The full set of proteins the proteome encoded by the human genome is more complex than those of invertebrates largely because vertebrates have rearranged old protein domains into a richer collection of new architectures. In other words, Humans have achieved innovations by rearranging and expanding tried-and-true strategies from other species - not by developing novel strategies of their own.
Another way we humans innovate is by expanding protein families. Scientists report that some 60 percent of protein families in humans are superfamilies, with more family members than in any of the other four sequenced organisms. This suggests that gene duplication has been a major evolutionary force during vertebrate evolution.
Many of the families that have undergone expansions in humans are involved in distinctive aspects of vertebrate physiology. One example is the family of immunoglobulin Ig domains, first identified in antibodies thirty years ago. Classic Ig domains are absent from the yeast and the mustard weed. In vertebrates, the Ig repertoire includes a wide range of immune functions and is a testament to the notion that a single family of proteins can be extremely versatile, mounting a multi-pronged, orchestrated response to infection. Another example of a family that has proliferated in humans is epithelial proteins such as keratin.
This protein family probably grew to support and line the various organs in humans, including the lining of the small intestine and cilia in the inner ear. Finally, at least some families of genes in the human genome seem to be shrinking. More than half of our smell receptors seem to be broken. This is curious, given that smell receptors belong to one of the biggest gene families with more than members.
It seems that despite the high priority given to smell by our vertebrate ancestors, humans seem to have lost their dependence on it. Smell was key to survival in our vertebrate ancestors, but for us, vision is probably more important for survival. Only a tiny fraction, about 1.
The vast majority of the genome-more than 50 percent-consists of repetitive sequences, or "junk DNA," that have been hopping around the genome for 3 billion years. Junk DNA has helped scientists come to terms with one of the human genome's most perplexing paradoxes-that our genome is times larger than that of baker's yeast but times smaller than that of amoeba! Scientists chalked up this discrepancy in genome sizes to the existence of junk DNA collecting in organisms and the lack of routine housecleaning. Even so, scientists didn't fully appreciate the value of junk DNA-until now.
Junk DNA represents a rich fossil record of clues to our evolutionary past. It is possible to date groups of repeats to when in the evolutionary process they were "born" and to follow their fates in different regions of the genome or in different species. The HGP scientists used 3 million such elements as dating tools.
Based on such "DNA dating," scientists can build family trees of the repeats, showing exactly where they came from and when. These repeats have reshaped the genome by rearranging it, creating entirely new genes, and modifying and reshuffling existing genes. Calculating the evolutionary age of the repeat elements in the human genome has turned up a wealth of interesting, shocking, and curious facts about the stuff that we are made of see next two vignettes for details. One of the most interesting aspects of the repeat elements is that as a species, we humans seem to have a tendency to be pack-rats-in stark contrast to other organisms.
The amount of junk we've accumulated in our genome far exceeds those collected by our early evolutionary cousins with the amoeba being a notable exception. We have a greater percentage of repeats in our genomes percent-than the mustard weed 11 percent , the worm 7 percent or the fly 3 percent. Also, our repeat elements are much older-actually, really ancient-when compared to those found in the other organisms.
We have been slow to clean out our drawers, closets, or attics," says Arian Smit, bioinformatics scientist at the Institute for Systems Biology. When we calculate the half-life of some of these elements, we find that while the fly did its last house-cleaning 12 million years ago, mammals last cleaned house million years ago. These features of the human genome probably apply to all mammals. But one feature-shockingly-does not. It seems that there has been a dramatic decrease in repeats in the human genome over the past 50 million years.
It's as if we decided 50 million years ago to stop collecting junk. In contrast, there seems to be no such decline in repeats in rodents. What's more, it seems as though some of our really ancient junk is extinct and some other junk is teetering on the brink of extinction. I believe my daughter is far too young to see those graphic images.
Watching this tragedy will transform her. Five-year-olds in Haiti fear the morning, the night, and every second in between. My daughter, on the other hand, fears the hairbrush I put to her head before sending her to school. I sit my daughter down next to me. She watches intently. Dazed and dusty people wander about aimlessly. The bad thing had just happened.
There are no bandages to cover the scary Play-Doh on eyes, arms, legs, and faces. There are no shrouded human forms in the middle of the street—not yet. The heaps of half-dressed mannequins with muddy hair and missing limbs have yet to be piled in wheelbarrows and dump trucks. She blinks hard, adjusting her eyes. The baby looks like an antique doll that had fallen off a shelf and lost a few parts. The truth will have to be rationed carefully—told in increments—over time.
They need snacks. And juice boxes. Hers is the face of a nation. Hypnotic green eyes of an icon, watching in spellbinding stillness. Ripe lips frozen for seventeen years, never to disclose confidences. She looks different now. Haiti—Girl Carrying Basket stares down from the yellowed calendar tacked on the kitchen wall.
Perhaps one that weighs as much as the basket on her head, but I was content not knowing. Yes, now I have to find Haiti—Girl Carrying Basket, who for seventeen years kept a quiet vigil above the coffee canister. She vows to win this war against poverty. She poses, remembering to rub her blue eyes to summon the redness. The sadness. Tears and dark circles are priceless in this place.
There will be talk shows. I will say Good Morning to everyone in America. Sak pase? Yes, the sadder the eyes the better. Look at these desperate children.
Short Story Collections Not To Be Missed This Summer
See how I feed them. See how I care for them. See how much I love them. See how often I bury them.
Digging little graves with my own hands. Take a picture. But I do. Oh yes, I do. Take another picture. Let me fix my blouse. A little cleavage goes a long way. What do you say, Mister Photographer? Take another. Somebody come quick.
Short Stories: Journeys - PopMatters
Find me a baby to hold in my arms. Not this one.
This one looks too healthy. Give me that one over there. That one is perfect. Sunken eyes. A deformed head. Ashy skin. Parched lips. Oh, yes, thank you. Thank you, this baby will do well. This will be great in the press. The talk show hostess will cry out In the Name of God!
Take a picture, mister photographer. I can go on all the talk shows in the world, but a picture is worth a million words—at a dollar each! Her writings have been published in numerous literary journals, including the Caribbean Writer , Meridians , Calabash , Peregrine , and Smartish Pace , among others. Ulysse lives in Maryland with her husband and daughter. Drifting is her first book of fiction.
1. The Refugees by Viet Thanh Nguyen: £12.99, Little, Brown
Reverse-Gentrification of the Literary World. Ulysse: Three Vignettes Katia D. They need everything. And another.