Birthmarks are congenital marks on the skin that appear at birth and occasionally disappears spontaneously. The term nevus refers to a benign cutaneous tumor consisting of blood capillaries. Such tumors, which rarely spread from their original site and are not dangerous, vary in color according to whether the capillaries composing them carry arterial or venous blood. The popularly termed cherry marks and port-wine stains (shown below) are nevi on a level with the surface of the skin. Certain other vascular nevi, commonly known as strawberry or raspberry marks (scientifically known as hemangiomas), are slightly elevated above the surface. These can appear anywhere on the body's surface, including the airway within the nose. The former Soviet ...

An unexpected link in mice has been found between gray hair, the transcription factor MITF, and the innate immune in a recent study published in PLOS Biology.

First, a discussion on the innate immune system: The innate immune system is the immune system you're born with. This includes your skin and other barriers which prevent disease entering the body, in addition to specialized cells that activate inflammation in response to foreign invaders. Technically, every cell in your body except for red blood cells, are capable of generating an immune response, and this includes the production of a signaling protein known as interferon.

Microphthalmia-associated transcription factor (MITF) is best known for its role in regulating the many functions ...

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 ...

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 ...

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 ...

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 ...

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 ...