These are white tigers at Chimelong Safari Park in China. Credit: Chimelong Safari Park

Why do some tigers have white coats? Researchers from China's Peking University have discovered that white tigers owe their unique coloration to a gene mutation in the pigment gene SLC45A2. This gene inhibits the production of red and yellow pigments in white tigers but does not appear to alter black. Like orange Bengal tigers, white tigers have distinctive black stripes. The SLC45A2 gene has also been associated with light coloration in modern Europeans and in animals such as fish, horses, and chickens.

According to researcher Shu-Jin Luo, "The white tiger represents part of the natural genetic diversity of the tiger that is worth conserving, but is now seen only in captivity." The researchers advocate for the possible reintroduction of white tigers into the wild. Current white tiger populations only exist in captivity as wild populations were hunted out in the 1950s.

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• White Tiger Mystery Solved (Science Daily)

This image shows a newly discovered miniature spider species Mysmena wawuensis. Credit: Shuqiang Li; CC-BY 3.0

Researchers have discovered two new spider species in an area in China known for its giant panda population. These miniature orb-weaving spiders are less than 2 mm in length and live in obscure places such as in caves, moss, and moist leaf litter. Due to their size, these eight-eyed creatures are among the least studied spiders of their kind.

The spiders were discovered in the Sichuan and Chongqing regions. Spiders from the Mysmenidae family, to which these newly discovered spiders belong, are thought to widely inhabit tropical and subtropical regions. The new species have a unique body shape that is characterized by an over-sized spherical body.

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• Two Miniature Spider Species Discovered (Science Daily)

A protein known as ALKBH7 plays a key role in controlling the programmed necrosis pathway. To determine the location of ALKBH7 in cells, MIT researchers engineered these cells to express ALKBH7. The cells appear yellow where ALKBH7 is present in the mitochondria. Credit: Jennifer Jordan and Dragony Fu

MIT researchers have identified a protein, ALKBH7, that is crucial to a cell death process known as programmed necrosis. When cells suffer unrepairable DNA damage, the programmed necrosis pathway is initiated so that the cells rupture and die. This prevents the damaged cells from potentially developing into cancer cells. Cancer cells are sometimes resistant to another type of programmed cell death known as apoptosis.

According to researcher Leona Samson, "People really used to think of necrosis as cells just falling apart, that it wasn't programmed and didn't require gene products to make it happen. In the last few years it has become more clear that this is an active process that requires proteins to take place." These findings could mean potential new targets for cancer drug treatments. The drugs could work in a similar manner to the necrosis protein ALKBH7 to cause cancer cells to self destruct.

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• Study IDs Key Protein for Cell Death (Science Daily)

This is a colony of human embryonic stem cells (ESCs) (upper portion) generated by somatic cell nuclear transfer (SCNT). Credit: Cell, Tachibana et al.

For the first time, researchers have successfully produced human embryonic stem cells using a technique called somatic cell nuclear transfer (SCNT). This process involves removing the nucleus from an egg cell and replacing it with the nucleus of another cell. In the study, human skin cell nuclei were transplanted into unfertilized enucleated (removed genetic material) egg cells. These cells went on to develop and produce embryonic stem cells. The stem cells had no chromosomal abnormalities and normal gene function.

According to researcher Shoukhrat Mitalipov, "A thorough examination of the stem cells derived through this technique demonstrated their ability to convert just like normal embryonic stem cells, into several different cell types, including nerve cells, liver cells and heart cells. Furthermore, because these reprogrammed cells can be generated with nuclear genetic material from a patient, there is no concern of transplant rejection." Stem cell therapies could be used to treat individuals with conditions such as multiple sclerosis, spinal cord injuries, cardiac disease, and Parkinson's disease.

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• Human Skin Cells Converted Into Embryonic Stem Cells (Science Daily)