Category Archives: DNA

DNA sequencing technology is helping scientists unravel questions that humans have been asking about animals for centuries. By mapping out animal genomes, we now have a better idea of how the giraffe got its huge neck and why snakes are so long. Genome sequencing allows us to compare and contrast the DNA of different animals and work out how they evolved in their own unique ways. But in some cases we're faced with a mystery. Some animal genomes seem to be missing certain genes, ones that appear in other similar species and must be present to keep the animals alive. These apparently missing genes have been dubbed "dark DNA". And its existence could change the way we think about evolution. My colleagues and I first encountered this phenomenon when sequencing the genome of the sand rat (Psammomys obesus), a species of gerbil that lives in deserts. In particular we wanted to study the gerbil's genes related to the production of insulin, to understand why this animal is particularly susceptible to type 2 diabetes. But when we looked for a gene called Pdx1 that controls the secretion of insulin, we found it was missing, as were 87 other genes surrounding it. … Continue reading →

Transcript for DNA results indicate human remains could be Natalee Holloway We turn to new details in the Natalee Holloway investigation. DNA results on the human remains recently found in aruba could they belong to the young woman who disappeared more than 12 years ago? ABC's linsey Davis is here with more on that story. Good morning, linsey. Good morning, Amy. This grisly discovery could be a major development. After more than a decade Natalee Holloway's parents may finally be on the eve of closure in the case of their young daughter who went to aruba to celebrate her high school graduation and never came back. This morning a possible development that may finally help solve the 12-year mystery. Preliminary DNA tests reportedly show newly discovered remains in the search for Natalee Holloway are from a caucasian person of European descent matching the profile of the missing 18-year-old who was declared dead in 2012. Her body was right here. Reporter: These DNA results come after bones were found, a new discovery based on a tip from a former roommate of a friend of Joran van Der sloot, a prime suspect in the case. The investigation is part of a six-part … Continue reading →

PLEASANTON At the IntegenX Inc. headquarters on Stoneridge Drive, employees are hard at work developing upgrades to their product: a small machine that can unravel DNA code in less than two hours. The company is a leader in the market for what is known as rapid DNA technology, which has shortened the time it takes to process DNA testing from weeks to about 90 minutes. It could get a boost from recently passed legislation that sets new federal rules for how law enforcement processes DNA, something the companys leaders have been lobbying for in the past few years. IntegenX CEO Robert Schueren called the passage of the bill the Rapid DNA Act of 2017 a landmark day in fighting crime. The bill will allow law enforcement agencies to perform real-time DNA testing at the time of arrest at their own booking stations, comparing samples to profiles in the FBIs Combined DNA Index System (CODIS) under guidelines set by the FBI. Using the technology, investigators can find out whether an arrestees DNA matches the DNA in the FBI database while suspects are still being processed. But the prospect raises privacy concerns for some. Before the legislation, law enforcement agencies had to … Continue reading →

The first sign of successful in vitro fertilization, after co-injection of a gene-correcting enzyme and sperm from a donor with a genetic mutation known to cause hypertrophic cardiomyopathy. Courtesy of OHSU hide caption The first sign of successful in vitro fertilization, after co-injection of a gene-correcting enzyme and sperm from a donor with a genetic mutation known to cause hypertrophic cardiomyopathy. Scientists have been tinkering with the DNA in humans and other living things for decades. But one thing has long been considered off-limits: modifying human DNA in any way that could be passed down for generations. Now, an international team of scientists reports they have, for the first time, figured out a way to successfully edit the DNA in human embryos without introducing the harmful mutations that were a problem in previous attempts elsewhere. The work was published online Wednesday in the journal Nature. "It's a pretty exciting piece of science," says George Daley, dean of the Harvard Medical School, who was not involved in the research. "It's a technical tour de force. It's really remarkable." The research is ultimately aimed at helping families plagued by genetic diseases. The new experiment used a powerful new gene-editing technique to correct … Continue reading →

A Mycenaean woman depicted on a fresco at Mycenae on mainland Greece. Yann Forget/Wikimedia Commons By Ann GibbonsAug. 2, 2017 , 1:00 PM Ever since the days of Homer, Greeks have long idealized their Mycenaean ancestors in epic poems and classic tragedies that glorify the exploits of Odysseus, King Agamemnon, and other heroes who went in and out of favor with the Greek gods. Although these Mycenaeans were fictitious, scholars have debated whether todays Greeks descend from the actual Mycenaeans, who created a famous civilization that dominated mainland Greece and the Aegean Sea from about 1600 B.C.E. to 1200 B.C.E., or whether the ancient Mycenaeans simply vanished from the region. Now, ancient DNA suggests that living Greeks are indeed the descendants of Mycenaeans, with only a small proportion of DNA from later migrations to Greece. And the Mycenaeans themselves were closely related to the earlier Minoans, the study reveals, another great civilization that flourished on the island of Crete from 2600 B.C.E. to 1400 B.C.E. (named for the mythical King Minos). The Lion Gate was the main entrance to the Bronze Age citadel of Mycenae, the center of the Mycenaean civilization. RnDmS/iStockphoto The ancient DNA comes from the teeth of … Continue reading →

Molecular model of the lesion that the bacterial toxin yatakemycin forms on DNA. Credit: Elwood Mullins / Vanderbilt One of the most potent toxins known acts by welding the two strands of the famous double helix together in a unique fashion which foils the standard repair mechanisms cells use to protect their DNA. A team of Vanderbilt University researchers have worked out the molecular details that explain how this bacterial toxinyatakemycin (YTM)prevents DNA replication. Their results, described in a paper published online July 24 by Nature Chemical Biology, explain YTM's extraordinary toxicity and could be used to fine-tune the compound's impressive antimicrobial and antifungal properties. YTM is produced by some members of the Streptomyces family of soil bacteria to kill competing strains of bacteria. It belongs to a class of bacterial compounds that are currently being tested for cancer chemotherapy because their toxicity is extremely effective against tumor cells. "In the past, we have thought about DNA repair in terms of protecting DNA against different kinds of chemical insults," said Professor of Biological Sciences Brandt Eichman. "Now, toxins like YTM are forcing us to consider their role as part of the ongoing chemical warfare that exists among bacteria, which can … Continue reading →

Parsing the creatures 2 billion base pairs, Feschotte and his colleagues did stumble on something strange. We found some very weird transposons, he said. Because these oddball parasite sequences didnt appear in other mammals, they were likely to have invaded after bats diverged from other lineages, perhaps picked up from an insect snack some 30 to 40 million years ago. Whats more, they were incredibly active. Probably 20 percent or more of the bats genome is derived from this fairly recent wave of transposons, Feschotte said. It raised a paradox because when we see an explosion of transposon activity, wed predict an increase in size. Instead, the bat genome had shrunk. So we were puzzled. There was only one likely explanation: Bats must have jettisoned a lot of DNA. When Kapusta joined Feschottes lab in 2011, her first project was to find out how much. By comparing transposons in bats and nine other mammals, she could see which pieces many lineages shared. These, she determined, must have come from a common ancestor. Its really like looking at fossils, she said. Researchers had previously assembled a rough reconstruction of the ancient mammalian genome as it might have existed 100 million years … Continue reading →

Definition: DNA (deoxyribonucleic acid) is a type of macromolecule known as a nucleic acid. It is shaped like a twisted double helix and is composed of long strands of alternating sugars and phosphate groups, along with nitrogenous bases (adenine, thymine, guanine and cytosine). DNA is organized into structures called chromosomes and housed within the nucleus of our cells. DNA is also found in cell mitochondria. DNA contains the genetic information necessary for the production of cell components, organelles, and for the reproduction of life. Protein production is a vital cell process that is dependent upon DNA. Information contained within the genetic code is passed from DNA to RNA to the resulting proteins during protein synthesis. DNA is composed of a sugar-phosphate backbone and nitrogenous bases. In double-stranded DNA, the nitrogenous bases pair up. Adenine pairs with thymine (A-T) and guanine pairs with cytosine (G-C). The shape of DNA resembles that of a spiral staircase. In this double helical shape, the sides of the staircase are formed by strands of deoxyribose sugar and phosphate molecules. The stair steps are formed by the nitrogenous bases. The twisted double helix shape of DNA helps to make this biological molecule more compact. DNA is … Continue reading →

Genes are the blueprints of life. Genes control everything from hair color to blood sugar by telling cells which proteins to make, how much, when, and where. Genes exist in most cells. Inside a cell is a long strand of the chemical DNA (deoxyribonucleic acid). A DNA sequence is a specific lineup of chemical base pairs along its strand. The part of DNA that determines what protein to produce and when, is called a gene. First established in 1985 by Sir Alec Jeffreys, DNA testing has become an increasingly popular method of identification and research. The applications of DNA testing, or DNA fingerprinting within forensic science is often what most people think of when they hear the phrase. Popularized by television and cinema, using DNA to match blood, hair or saliva to criminals is one purpose of testing DNA. It is also frequently used for other benefits, like wildlife studies, paternity testing, body identification, and in studies pertaining to human dispersion.While most aspects of DNA are identical in samples from all human beings, concentrating on identifying patterns called microsatellites reveals qualities specific and unique to the individual. During the early stages of this science, a DNA test was performed using … Continue reading →

A DNA-based sunscreen that not only stops harmful ultraviolet (UV) light, but also becomes more protective the longer you expose it to UV rays? Thats the dazzling premise behind a recent study published in the journal Science Reports. While sunscreen isnt the only form of sun protection (theres always protective clothing and floppy hats), the reality is that most of us just skip it. A 2015 study in Journal of the American Academy of Dermatology found that only 14.3 percent of men and 29.9 percent of women routinely use sunscreen when they are in outside for more than an hour. This wouldnt be a problem, except, Ultraviolet light is a carcinogen, Guy German a biomedical researcher at Binghamton University in New York and an author on the study, tells PopSci. We know it can give you a tan, but it can also cause cancer as well. While dermatoepidemiologists (scientists who study diseases of the skin) suspect that sunlight causes cancer because it damages DNA in our cells, German and his colleagues were looking at DNA in an entirely different way. They wondered what would happen if they exposed DNA film, essentially a thin sheet of the stuff, to the same … Continue reading →