FEB 21, 2018 06:00 PM PST

Clues to Immortality From the Fruit Fly Genome

WRITTEN BY: Carmen Leitch

The secrets to immortality may lie in an unexpected place - fruit fly stem cells. Researchers led by Howard Hughes Medical Institute (HHMI) Investigator Yukiko Yamashita have found that some stem cells have a genetic trick to remain young forever across generations. While some areas of the fruit fly genome get shorter as they age, some reproductive cells are able to fix that shortening. Once observed only in yeast, this work, reported in eLife, has revealed more about aging, and how some cells can avoid it.

This work focused on critical genes in ribosomal DNA, rDNA. Ribosomes are cellular organelles that act as protein factories. That rDNA is repeated in several areas of the genome because many ribosomes are needed to make all of the proteins the body needs. Five chromosomes each have spots with hundreds of copies of rDNA. However, that type of redundant sequence can be difficult for cells to replicate accurately every time cell division happens.

"The end result is that some copies are lost every cycle," Yamashita explained. "They are popping out of the chromosome."

This loss has been seen in single-celled yeast, but until now nothing has been known about the role of rDNA in aging in multicellular organisms. Yamashita and her team assessed rDNA genes found in the stem cells of fruit fly testes. Those are called germline stem cells and can divide continuously to make a sperm cell as well as a copy of themselves each time.

Fruit flies carry rDNA hotspots on X and Y chromosomes. Old males were found to have fewer rDNA genes on their Y chromosome compared to young males. It was determined that the shrunken Y chromosome can also be passed on to the next generation. Elderly fruit fly fathers were found to pass down fewer rDNA genes to their sons. Yamashita and colleagues saw that sons born to old fathers had significantly fewer rDNA copies than sons of young fathers.

The fruit fly has been used extensively genetics research. / Image credit: Wikimedia Commons/Sanjay Acharya

However, something surprising was seen after following up on those sons. Many of them recovered the loss of rDNA. "This recovery was something we really didn't expect," Yamashita said. 

It may be that stem cells and rDNA rejuvenation are connected. The researchers have yet to examine this phenomenon in females, or if similar mechanisms are seen in humans.

Yamashita suggested that these types of processes may indeed be at work in some kinds of human cells, like stem cells or cancer cells. "Of course, we are not flies," she noted, but she thought it likely that some immortal cells carried by people can perform the same rejuvenation technique to stop the decline of rDNA.

Sources: AAAS/Eurekalert! Via HHMI, eLife

About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
AUG 23, 2018
Genetics & Genomics
AUG 23, 2018
Growing Plants That Don't Need as Much Water
Parts of our world already have to deal with periods of drought, and it may only get worse....
SEP 05, 2018
Videos
SEP 05, 2018
Mosquitoes' Attraction to You May be Genetic
Are you a person that seems always to get bitten by mosquitoes?...
SEP 14, 2018
Genetics & Genomics
SEP 14, 2018
Gout Risk Linked to Small Genetic Change
Interestingly, this genetic variation is not within the coding portion of a gene; it lies adjacent to it....
OCT 13, 2018
Genetics & Genomics
OCT 13, 2018
A Better Way to Analyze Epigenetic Tags
This improved technology does not harm the DNA under analysis....
OCT 21, 2018
Genetics & Genomics
OCT 21, 2018
The Genetic Cause of Severe Childhood Epilepsy is Revealed
This work has opened up new therapeutic avenues that the scientists will be exploring....
NOV 07, 2018
Genetics & Genomics
NOV 07, 2018
Hunting Down the microRNAs That Influence Disease
Researchers want to identify the tiny, non-coding RNAs that control gene expression - and contribute to disease....
Loading Comments...