Bone marrow, the spongy tissue inside long bones, produces new blood cells and helps the lymphatic system work properly. But it may also turn out to be a progressively hostile microenvironment that induces vascular dysfunction and ossification, or hardening, of blood vessels.
Rhonda Prisby, who is using a rat model to study bone vascular physiology and morphology, was recently surprised when she used light microscopy to look at bone marrow vessels. (more…)
A study dating the age of more than 1 million single-letter variations in the human DNA code reveals that most of these mutations are of recent origin, evolutionarily speaking. These kinds of mutations change one nucleotide – an A, C, T or G – in the DNA sequence. Over 86 percent of the harmful protein-coding mutations of this type arose in humans just during the past 5,000 to 10,000 years.
Some of the remaining mutations of this nature may have no effect on people, and a few might be beneficial, according to the project researchers. While each specific mutation is rare, the findings suggest that the human population acquired an abundance of these single-nucleotide genetic variants in a relatively short time. (more…)
