Nearly 80% of U.S. dairy cows have their horns removed each year to protect their handlers and fellow cattle. But the practice, which is both painful and expensive, has come under increasing scrutiny from animal rights activists. Now, science may be coming to the rescue: A group of researchers announced last week that they successfully edited the genomes of dairy cows to make them hornless. The scientists used the transcription activator-like effector nucleases DNA editing technique to introduce a natural allele linked to hornlessness into dairy cow embryos. Five healthy calves were born, all without horns (above, left), the researchers report in a letter in Nature Biotechnology. The allele - called POLLED - is much more common in beef catt [ ... ]
According to a study published in the medical journal eLife, researchers found that specific combinations of gut bacteria produce substances that affect myelin content and cause social avoidance behaviors in mice.
Researchers transferred fecal bacteria from the gut of depressed mice to genetically distinct mice exhibiting non-depressed behavior. The study showed that the transfer of microbiota was sufficient to induce social withdrawal behaviors and change the expression of myelin genes and myelin content in the brains of the recipient mice.
In an effort to define the mechanism of gut-brain communication, researchers identified bacterial communities associated with increased levels of cresol, a substance that has the ability to pass the bloo [ ... ]
The darker bird pictured above belongs to a family of trickster birds known as the cuckoo. The common cuckoo is notorious for creeping into other birds' nests and laying their eggs, leaving the hosts to raise the chick as their own. This mechanism is known as brood parasitism, and it is quite common in the animal kingdom. However, not all cuckoos are dead-beat parents, many do raise their own young. The cuckoo birds that do use this mechanism are obligate brood parasites, meaning that they only reproduce in this fashion.
The best-known example is the European common cuckoo (shown above). The shells of the eggs of brood-parasites are usually thick. They have two distinct layers with an outer chalky layer that is believed to provide resistan [ ... ]
When it comes to genome size, a rare Japanese flower, called Paris japonica, is the current heavyweight champ, with 50 times more DNA than humans. It is a slow growing perennial that sports a rare, showy white star-like flower above a single whorl of about eight stem leaves. The exceptionally large genome of P. japonica is due to the fact that it's an octoploid, meaning it has four sets of chromosomes - on the contrary, humans are diploid (two sets). Its 40 chromosomes consist of 150 billion base pairs of DNA per cell, therefore making its genome the largest known genome of any living organism. In fact, the DNA from a single cell could theoretically stretch out to be longer than 300 feet (91 m). [ ... ]
This week in Science, researchers led by genome sequencing pioneer Craig Venter report engineering a bacterium to have the smallest genome - and the fewest genes - of any freely living organism. Known as Syn 3.0, the new organism has a genome whittled down to the bare essentials needed to survive and reproduce, just 473 genes. However, the function of 149 of Syn 3.0's 473 genes remain unknown.
As Syn 3.0's name suggests, it’s not the first synthetic life made by Venter. In 2010, Venter's team reported that they had synthesized the sole chromosome of Mycoplasma mycoides - a bacterium with a relatively small genome - and transplanted it into a separate mycoplasma called M. capricolum, from which they had previously extracted the DNA. After s [ ... ]
Vibratory urticarial is a ultra rare genetic condition that cause people to break out in hives if their skin is vigorously vibrated or rubbed. In fact, even drying yourself with a towel can cause hives, make your face flush, give you headaches, or produce the sensation of a metallic taste. According to a new study published this week, researchers found a mutation in a gene called ADGRE2 that codes for a receptor protein found on the surface of mast cells - immune cells in the skin that dump out inflammatory molecules such as histamines that increase blood flow to an area and can cause hives. The researchers observed that shaking mast cells in a dish breaks apart two subunits of this receptor protein, which prompts histamine release. In p [ ... ]
A landmark study, based on genetic analysis of nearly 65,000 people, has revealed that a person's risk of schizophrenia is increased if they inherit specific variants in a gene related to "synaptic pruning" - the elimination of connections between neurons. The findings represent the first time that the origin of this devastating psychiatric disease has been causally linked to specific gene variants and a biological process. They also help explain decades-old observations: synaptic pruning is particularly active during adolescence, which is the typical period of onset for schizophrenia symptoms, and brains of schizophrenic patients tend to show fewer connections between neurons. The gene, called component 4 (C4), plays a well-known role in t [ ... ]
Having more cells usually puts one at a higher risk for cancer - but not for the elephant. Despite packing 100 times as many cells as humans, this towering animal can keep cancer at bay thanks to extra copies of a tumor-fighting gene. Researchers found that Asian elephants harbor 30 to 40 copies of the gene that encodes the protein p53, one of the most important mechanisms for preventing cancer and maintaining cell division. If cells have DNA damage that could spawn tumors, p53 prevents them from dividing until they make repairs or spurs them to commit suicide. In contrast, humans sport only two copies of the gene for p53, and so does elephants’ closest living relative, the rock hyrax. The extra copies probably accumulated millions of yea [ ... ]
Scientists have discovered evidence that homosexuality is not a lifestyle choice, but rather is rooted in a person’s biology. While specific genes have not been found, a male twin study reveals that homosexuality may be caused by chemical modifications that alter gene activity. As the fetus develops, certain genes get turned on or off depending the chemicals the fetus is exposed to. These chemicals don't necessarily have to be chemicals ingested or inhaled by the mother, but could be an imbalance in a hormone, such as testosterone. As adults, genes can also activate and deactivated based on our environment. More research is needed, but scientists stress that these findings shouldn’t be used to produce tests for homosexuality or a misguid [ ... ]
Beauty may be in the eye of the beholder, but what’s influencing our eye? Scientists reveal that it’s not genetics but life experiences that lead us to find one face more attractive than another. This finding furthers the on-going debate of nature versus nurture.
Here's how the study went down: Researchers asked 547 pairs of identical twins and 214 pairs of same-gender fraternal twins to view 200 faces and rate them on a scale of one to seven, with one being the least attractive and seven the most attractive. A group of 660 non-twins then completed the same survey. If genes were more involved in facial preference, identical twins would have had similar ratings; if the influence of a familial environment carried more weight, fraternal twins w [ ... ]
It has to do with a single gene! More than a decade ago, researchers discovered that one gene (MC1R) on chromosome 16 plays an important role in giving people red hair. MC1R task is to make the protein melanocortin 1. This protein plays an important role in converting red pigment into black pigment. If you end up with only one mutated MC1R gene, red hair can appear in unwanted places, like your beard. When someone inherits two mutated versions of the MC1R-gene (one from each parent), less red pigment is converted into black pigment.
With a rare genetic condition called erythrism some insects, like this fluorescent pink katydid, develop an unusual reddish pigmentation. It's not enhanced in any way. The coloration (erythrism) is an adaptation sometimes found among katydids exposed to red or pink foliage, although this one was in the woods off the Appalachian Trail near Mount Peter, N.Y. [ ... ]
A rare condition, known as situs inversus, is when a person has their major organs mirrored from their normal positions. So, for example, the heart would be on the right side of the body, or the liver and gall bladder are on the left side. It is a congenital condition (meaning it's tied to your genetics) that affects 1 in 20,000 people - including Spanish-born singer Enrique Iglesias.
Situs inversus is generally an autosomal recessive genetic condition, although it can be X-linked or found in identical "mirror image" twins.
Before you get any ideas that we're cloning wholly mammoths back into the 21st century, it's not that. An American geneticist has extracted DNA from the frozen remains of a long-dead mammoth found on Wrangel Island in the Arctic Ocean (shown above), created a synthetic replica of it, and implanted it into elephant cells that have been isolated in a petri dish, using a new technique of DNA splicing that allows for unprecedented accuracy.
The technique used to join synthetic mammoth DNA fragments with the genetic code of an elephant is called CRISPR/Cas9, and while it’s been recently used to create transgenic organisms, this is the first time it’s been used on the DNA of an extinct organism.
Kösen's height was caused by the production of too much growth hormone due to a tumour in his pituitary gland. The tumour was eventually removed in 2010 through revolutionary gamma-knife surgery. Amge has a form of dwarfism, caused by a mutation in a bone growth gene. [ ... ]
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