Scientists find that genes have help in determining our traits

Dec 27, 2010

(PhysOrg.com) -- For decades, biology textbooks have been clear – our traits are the product of our genes. But a new study by Yale University researchers published Dec. 26 in Nature Genetics suggests another mechanism can regulate variations of traits even in genetically identical individuals.

For decades, biology textbooks have been clear – our traits are the product of our genes. But a new study by Yale University researchers published Dec. 26 in Nature Genetics suggests another mechanism can regulate variations of traits even in genetically identical individuals.

A particular type of RNA works in concert with a common protein to protect organisms from harmful genetic variations without the help of genes, reports Haifan Lin, director of the Yale Stem Cell Center, professor of cell biology and genetics and senior author of the paper.

“This mechanism may help explain how ordinary cells such as fibroblasts can be converted to and why some cancers develop at random,” Lin said.

The theory that factors other than genes are responsible for an organism’s traits, or phenotype, has been around for almost 70 years but has only gained steam in the past decade. For instance, cloned animals are often born with different colors than the animals that are the source of their DNA. But what causes these changes remained unclear.

About a decade ago, scientists found that a noticeable percentage of flies lacking a protein called Hsp-90 ended up with bizarre and random abnormalities such as legs growing where eyes should be. It seemed clear that Hsp-90 protected an organism against harmful genetic variations in its genome. Yet, since Hsp-90’s role is to mobilize other molecules to respond to stress, researchers suspected other factors were involved.

One school of thought suspected that Hsp-90 prevents the display of random abnormalities by suppressing the activities of “jumping genes” that can relocate to other areas of the genome and cause mutations. However, the Yale researchers report that their work with flies shows that a type of small RNA called Piwi-interacting RNA, or piRNA, acts in concert with Hsp-90 and another molecule to prevent both the creation of variants and the activation of existing genetic variants. do play a role in protecting against harmful variations but probably work through actions of the molecules piRNA and Hsp-90.

Lin, who studies piRNAs in reproductive cells and stem cells, says that the variations in levels of Hsp-90 and piRNAs among individual cells of the same type might explain why a small number of ordinary cells can be reprogrammed into stem cells and also why harmful mutations are created in some cancers.

“This study shows that we still have a lot to learn about the most basic principles of gene regulation,” Lin commented. “Studies of this kind may provide missing puzzles in our understanding of normal development and malignancies.”

Vamsi Ganguraju, working in Lin’s lab, was first author of the paper. Other Yale authors include Molly M Weiner, Jianquan Wang and Xiao A Huang.

The study was funded by the G. Harold and Leila Y. Mathers Foundation and the NIH.

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kevinrtrs
1 / 5 (4) Dec 28, 2010
works in concert with a common protein to protect organisms from harmful genetic variations without the help of genes,

piRNA, acts in concert with Hsp-90 and another molecule to prevent both the creation of variants and the activation of existing genetic variants

It's getting more and more difficult for those who cling to evolution to escape the facts.
The whole DNA system and now even some extraneous factors are designed to PROTECT against harmful mutations. Just about any random, unspecified mutation is either useless or harmful. There are very few random mutations that are actually good. This is not to be confused with the switching on or off of already existing genes which would in most cases be the source for speciation.

Ethelred
5 / 5 (2) Dec 28, 2010
It's getting more and more difficult for those who cling to evolution to escape the facts.
Where is anything in that article supporting that nonsense?
The whole DNA system and now even some extraneous factors are designed to PROTECT against harmful mutations.
Yet they happen anyway. There are even chemicals that cells can and sometimes do produce that ENCOURAGE mutations.
Just about any random, unspecified mutation is either useless or harmful.
Not quite all. Just enough for slow evolution to occur under normal conditions. Under stress mutagenic compounds are produced in all known species. Thus increasing the rate of mutation under difficult conditions.
This is not to be confused with the switching on or off of already existing genes which would in most cases be the source for speciation.
Switching genes on or off by RNA segments is epigenetic and does not lead to inheritable change.

By the way, when was the Flood in your opinion?

Ethelred