Scientists discover stem cell origin of neck and shoulders

Scientists believe that instead of groups of stem cells creating the skeletal and muscle structure separately they actually appear to make them together as a sort of "composite." This could have significant implications for clinical medicine and our understanding of vertebrate evolution.

Scientists at the Wolfson Institute for Biomedical Research of UCL … used a new genetic technique to tag embryonic stem cells and then trace them to the adult animal.

They discovered that instead of homogeneous groups of stem cells making up the bones of the shoulder and neck and others making the muscles, a newly discovered group of stem cells called mesenchymal stem cells make both the muscles and the point where they join the skeleton.

The researchers believe their results, published in 'Nature', show that the skeleton and muscles of vertebrates should not be seen as separate but instead are composites, with the boundaries between cell groups blurred around the body. …

Dr. Georgy Koentges, one of the lead researchers at UCL, said, "Anatomists and everyone else would look at the skeleton and assume that the bone structures are uniform and are the basic components of vertebrate organization. Our research suggests this is wrong and actually groups of stem cells create not only the muscles of the neck and shoulder but also the skeletal structure where these muscles are attached. …"

As the joining points between muscles and bones have survived unaltered across hundreds of millions of years, researchers can also start to map cell territories into fossils. For the first time the research team have been able to trace what happened to a major shoulder bone that features in many extinct land animals. They found that it appears to survive in modern vertebrates as the scapular spine.

Koentges commented, "Now that we have identified these key players in forming the neck and the shoulders we can start looking for the genes that are on in these stem cells and which are ultimately responsible for evolutionary changes over millions of years. …"

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