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:5/1/2016)... Mission Viejo, CA (PRWEB) , ... May 01, 2016 , ... ... plan for those in need of chiropractic help. The agency offers a verity of ... and any chiropractic need. According to Chris Nelson at the firm, “Many insurance plans ...
(Date:4/30/2016)... ... 30, 2016 , ... The Hacking Medicine Institute ... critically evaluate and rank health-focused applications and connected devices for better disease monitoring ... and accurate information to help accelerate patient and provider adoption of clinically proven ...
(Date:4/30/2016)... ... 2016 , ... “Aging well is a challenge for all of us, but there are things we can do ... . “Research is showing more and more that there are simple, yet important steps that ... we age.” Top priorities Dr. Kohli’s recommends for her patients include;, , ...
(Date:4/29/2016)... ... April 29, 2016 , ... In an article ... shares her enthusiasm for Botox and lip injections, which she underwent in order to ... Coachella Valley Music and Arts Festival. The article explains that Ms. Mirmelli’s situation is ...
(Date:4/29/2016)... ... 2016 , ... Our bodies are bombarded daily by environmental and lifestyle factors ... stressors is to adopt a more healthful diet, but too many people think that ... Holistic Nutritionist and the creator of the Newport Beach Cleanse and 14-Day Eating Plan, ...
Breaking Medicine News(10 mins):
(Date:4/29/2016)... ReportsnReports.com adds "Pulmonary Arterial ... report that provides an overview of the PAH ... stages, therapeutics assessment by drug target, mechanism of ... type, along with latest updates, and featured news ... involved in the therapeutic development for Pulmonary Arterial ...
(Date:4/28/2016)... 28, 2016   Click here for supplemental ... (NYSE: DPLO), the nation,s largest independent specialty pharmacy, ... agreement to acquire Valley Campus Pharmacy, Inc., doing ... leading specialty pharmacy that provides individualized patient care, ... . In 2015, TNH generated approximately $400 million ...
(Date:4/28/2016)... April 28, 2016  The blood testing market in ... according to Kalorama Information and The Freedonia Group in ... nucleic acid testing.  The healthcare research firm said that ... developing blood collection stations and in improving testing at ... Information,s report, Blood Testing Market in China ...
Breaking Medicine Technology: