Calico cats aren't just good pets. They may also reveal a bit more about human genetics--and could even help combat the obesity epidemic.
Calico cats are known for their odd mix of orange, black and white fur. While their coloration is interesting, though, what's more fascinating is the fact that calico cats are always female. The orange fur color gene is located on one of the X chromosomes while the black color gene is located on the other. This means that the random silencing of one of the X's in each cell creates their patchwork fur. Yet researchers have been unclear exactly how a cell silences a chromosome.
"A cell's nucleus contains the genetic code, its DNA," said Elizabeth Smith, one of the researchers, in a news release. "But while the structure of the DNA was determined more than 50 years ago, and we're rapidly determining the position of specific genes on chromosomes, no one had visualized the DNA within an intact nucleus-and unfixed hydrated whole cell. We decided to try."
The scientists used a novel imaging technology--soft x-ray tomography. This gave them high-resolution views of the intact nucleus. In fact, they were able to identify one specific chromosome, the inactive X-chromosome, of female cells.
"The inactivation of one out of two X chromosomes in females is an enormously important epigenetic process," said Smith in a news release. "Uncovering how only one X chromosome is inactivated will help explain the whole process of epigenetic control, meaning the way changes in gene activity can be inherited without changing the DNA code. It can help answer other questions such as if and how traits like obesity can be passed down through generations."
In fact, body fat distribution has been associated with X chromosomes, according to Discovery News. This means that by learning more about these chromosomes and heritability, researchers could potentially find out which people are more at risk for obesity, which could allow them to take early intervention measures.
