Navigation Links
Study confirms males and females have at least 1 thing in common: Upregulating X
Date:10/24/2011

Chapel Hill, NC In a study published today in the journal Nature Genetics, a group of scientists including UNC biologist Jason Lieb, PhD, present experiments supporting a longstanding hypothesis that explains how males can survive with only one copy of the X chromosome. The finding provides clarity to a hotly debated topic in science and provides biologists with more information to interpret experiments involving genetic measurements in males and females.

"The issue is important because many diseases are tied to a defect in a regulatory mechanism within the cell," said Lieb, who is also a member of UNC Lineberger Comprehensive Cancer Center.

Women have two X chromosomes, while men have one X and one Y. The lack of a 'back up' copy of the X chromosome in males contributes to many disorders that have long been observed to occur more often in males, such as hemophilia, Duchene muscular dystrophy, and certain types of color blindness. Having only one copy of X and two copies of every other chromosome also creates a more fundamental problem with any other chromosome, the gene number imbalance resulting from having only one copy would be lethal. How can males survive with only one X?

Biologists have been debating how organisms and cells manage the imbalance between X and other chromosomes for years, with the dominant theory being that both sexes up-regulate the expression of X-linked genes, essentially doubling their expression to "2X" in males and "4X" in females. Then, to correct the imbalance that now appears in females (since they have the equivalent of "4" Xs now and 2 of every other chromosome), females then 'turn off' one of the hyperactive X chromosomes, resulting in a balanced "2X" expression of those genes across both sexes.

The advent of new technology based on RNA sequencing and proteomic analysis has given scientists more accurate ways to measure gene expression, and some results published in the last few years have not supported the idea that X chromosomes up-regulate.

Lieb and his colleagues re-analyzed data used in previous analyses, along with new data from humans, mice, roundworms, and fruit flies and found more evidence that the up-regulation hypothesis is correct but with some interesting twists across species. In mammals humans and mice both males and females up-regulate X chromosome gene expression and females then equalize expression by turning off the one X chromosome. In roundworms (C. elegans) the both female X chromosomes stay active, but the genes on both Xs are down-regulated by half to compensate in the females. In fruit files (Drosophilia melanogaster), males increase the expression of X chromosome genes, with no upregulation of X in females.

"There are several ways to get the same result and we are seeing how the dosage-balancing mechanism works in different species," says Lieb. "We also found that not all X-linked genes are dosage compensated to the same degree adding another layer of complexity for scientists who study gene regulation."


'/>"/>

Contact: Ellen de Graffenreid
edegraff@med.unc.edu
919-962-3405
University of North Carolina School of Medicine
Source:Eurekalert

Related medicine news :

1. Breast Reconstruction Boosts Womens Emotional Well-Being: Study
2. Hockey Fistfights Rarely Cause Injuries, Study Claims
3. Mayo Clinic study: PSA test valuable in predicting biopsy need, low-risk prostate cancer
4. Study finds no correlation between primary kidney stone treatment and diabetes
5. New Animal Study Might Explain Jet Lag Differences
6. Cell Phones Dont Raise Brain Cancer Risk, Study Says
7. More Than 1 in 4 U.S. Kids Witness Violence Between Parents: Study
8. Blood-pressure-lowering drug after stroke aids recovery, study finds
9. Study highlights issues faced by friends and family of the suicidal
10. Foreclosure Crisis Threatening Americans Health: Study
11. Car Crash Injury Risk Greater for Women Drivers: Study
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/13/2017)... AR (PRWEB) , ... October 13, 2017 , ... ... with locations throughout Arkansas that offers insurance and financial preparation services, is providing ... the Rock City Rescue organization. , Rock City Rescue is a locally recognized ...
(Date:10/13/2017)... ... October 13, 2017 , ... PurhealthRX , a ... utilizing Purzorb™ technology. Applying the Purzorb™process to full spectrum CBD oil will revolutionize the ... a CBD form that can be easily incorporated into liquid products, while reducing costs ...
(Date:10/13/2017)... (PRWEB) , ... October 13, 2017 , ... The Visiting ... Day Market. Featuring a collection of specialty vendors and unique items from across the ... and quality-focused health and wellness services offered by the VNA. The boutique will ...
(Date:10/13/2017)... (PRWEB) , ... October 13, 2017 , ... ... DevOps and Agile Software Development, has been awarded a contract by the Center ... Purchase Agreement (BPA) aims to accelerate the enterprise use of Agile methodologies in ...
(Date:10/12/2017)... Orleans, LA (PRWEB) , ... October 12, 2017 , ... ... centers in the U.S., announced today its plans to open a flagship location in ... will occupy the former Rooms To Go store next to Office Depot in the ...
Breaking Medicine News(10 mins):
(Date:10/5/2017)... , Oct. 5, 2017  In response ... of Oral and Maxillofacial Surgeons (AAOMS) released prescribing ... – to be used as a first-line therapy ... Recognizing the ... AAOMS White Paper "Opioid Prescribing: Acute and Postoperative ...
(Date:10/2/2017)... Oct. 2, 2017 Diplomat Pharmacy, Inc. (NYSE: ... Software and Consulting, LLC , and named its founder ... based in Tennessee , will operate ... expands EnvoyHealth,s service offerings for health care partners to ... "In an interoperable world, technology ...
(Date:10/2/2017)... 2017 The Rebound mobile app is poised to ... the tide of prescription drug addiction. The app empowers users ... and stepping down their dosage in a safe, controlled manner ... 2017; the first 100,000 people to sign up will enjoy ... ...
Breaking Medicine Technology: