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:2/18/2017)... ... February 17, 2017 , ... Focused ... innovation in the industry, according to the recent NEJM Catalyst Insights Report on ... of the NEJM Catalyst Insights Council, a qualified group of U.S. executives, clinical ...
(Date:2/18/2017)... ... 2017 , ... A new directory from the Senior Veterans ... connect elderly veterans of America's armed forces to a range of senior care ... on this year's increase in the Veterans Pension with Aid & Attendance for ...
(Date:2/17/2017)... ... 2017 , ... For the first time, International Scholarship and ... floor for the 2017 HIMSS Conference & Exhibition at the Orange ... than 40,000 healthcare industry professionals are expected at the conference, where they will ...
(Date:2/17/2017)... ... February 17, 2017 , ... Access today ... Exhibition in Orlando, Fla., February 19-23. Visitors to the company’s booth (#1778) will ... used electronic patient signatures solution in healthcare . , Since it first ...
(Date:2/17/2017)... ... February 17, 2017 , ... Cancer diagnostics workflow solution provider ... 20 – 22 in San Francisco. As part of the Tri-Conference expo, which ... workflow solution, as well as its new precision medicine platform, “Crosswalk Insight: Oncology™.” ...
Breaking Medicine News(10 mins):
(Date:2/16/2017)... 2017  AcelRx Pharmaceuticals, Inc. (Nasdaq: ... the development and commercialization of innovative therapies for ... Vincent J. Angotti has been appointed ... company,s board of directors, effective Monday, March 6, ... experience leading executive and commercial teams at public ...
(Date:2/16/2017)... , Feb. 16, 2017  Prescription pain medications ... department visit are necessary for long-term opioid use to ... Feb. 16 th edition of The New ... "Emergency physicians see more patients in acute pain than ... Parker , MD, FACEP, president of the American College ...
(Date:2/16/2017)... Research and Markets has announced the addition of the ... Function, Application, Cancer Type, Technology - Forecast to 2025" report ... ... grow at a CAGR of around 28.6% over the next decade ... Some of the prominent trends that the market is witnessing include ...
Breaking Medicine Technology: