“Latest Stem Cells News”

Each one of us receives approximately 60 new mutations in our genome from our parents.

This striking value is reported in the first-ever direct measure of new mutations coming from mother and father in whole human genomes published today.

For the first time, researchers have been able to answer the questions: how many new mutations does a child have and did most of them come from mum or dad? The researchers measured directly the numbers of mutations in two families, using whole genome sequences from the 1000 Genomes Project. The results also reveal that human genomes, like all genomes, are changed by the forces of mutation: our DNA is altered by differences in its code from that of our parents. Mutations that occur in sperm or egg cells will be ‘new’ mutations not seen in our parents.

Although most of our variety comes from reshuffling of genes from our parents, new mutations are the ultimate source from which new variation is drawn. Finding new mutations is extremely technically challenging as, on average, only 1 in every 100 million letters of DNA is altered each generation.

Previous measures of the mutation rate in humans has either averaged across both sexes or measured over several generations. There has been no measure of the new mutations passed from a specific parent to a child among multiple individuals or families.

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Like Samson, researchers in the field of stem cells have used the jawbone to make a point. Dr. Gordana Vunjak-Novakovic and her team at Columbia University have manipulated adult stem cells to grow one of the most difficult sections of bone to replace, the temporomandibular joint. This jawbone was created by allowing pluripotent cells harvested from marrow to grow in a scaffold that was fashioned to mimic the TMJ’s shape.

It is the first accurate and anatomically sized bone created by stem cells in a lab. Dr. Vunjak-Novakovic hopes that this new creation will serve as a proof of concept — if they can make the complex TMJ, they should be able to grow many other bones in your body. While this work is truly amazing, it still has some major hurdles to jump before it could be used to replace damaged or cancerous bones in humans (…)

Growing a fully functional part of the human body depends not only on coaxing adult stem cells to replicate and specialize, it also requires one heck of a nursery. The Columbia team has developed a bioreactor which provides all of the necessary nutrients for stem cells to develop into bone. The shape of the scaffold inside the bioreactor was defined through the use of many digital pictures. Which raises the possibility that eventual bone recipients could have the new body part made to look exactly like the old one. While the bioreactor is top notch, work still has to be done to find a way for the newly created bone to carry its own blood supply that can be easily adapted into the host (…)

from http://singularityhub.com/2009/10/13/stem-cells-used-to-create-new-jaw-bone/

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