Navigation Links
Pitt team finds protein that sets the stage for exchanges of DNA code in eggs and sperm

PITTSBURGH, Oct. 13 A team led by a scientist at the University of Pittsburgh School of Medicine has discovered a regulatory protein that influences where genetic material gets swapped between maternal and paternal chromosomes during the process of creating eggs and sperm. The findings, which shed light on the roots of chromosomal errors and gene diversity, appear in tomorrow's issue of Nature.

Most cells contain 46 chromosomes, half coming from each parent. But eggs and sperm, known as germ cells, have half as many so that when they combine to form an embryo, the correct chromosome number is maintained, explained senior author Judith Yanowitz, Ph.D., assistant professor of obstetrics, gynecology and reproductive sciences, Pitt School of Medicine, a member of the Magee-Womens Research Institute, and former staff associate at the Carnegie Institution of Washington, Baltimore.

"When germ cells form, segments of DNA are exchanged, or recombined, between maternal and paternal chromosomes, leading to greater diversity in the daughter cells," she said. "Our research reveals a protein that plays a key role in choosing where those crossovers occur."

Crossing over is essential for the correct movement, or segregation, of chromosomes into the germ cells. Failure to exchange DNA properly can lead to offspring with the wrong number of chromosomes and, in humans, defects in this process are a leading cause of infertility, Dr. Yanowitz noted.

Despite the importance of this process for development, little is known about the factors that influence where crossovers occur and how they are regulated. In the genome of the tiny round worm C. elegans that the researchers studied, gene recombination typically occurs toward the ends of the chromosomes, which contains fewer genes.

But the "crossover landscape," as Dr. Yanowitz calls it, changed in two ways in worms that had a mutation in a protein called X non-disjunction factor (xnd-1): crossovers instead occurred in the gene-rich, central areas of the chromosomes; and crossovers on the X chromosome often did not occur.

"This is the first gene in any system that is specifically required for the segregation of single chromosomes," she said. "The fact that this is the X chromosome is interesting because the sex chromosomes play a unique role both in germ line and general development."

These observations led the researchers to suggest that xnd-1affects the way chromosomes are packaged into the nucleus of the cell as a DNA protein complex known as chromatin. They further showed xnd-1 alters a component of chromatin that has been maintained through species evolution and that this packaging is directly responsible for the effects on crossover formation.


Contact: Anita Srikameswaran
University of Pittsburgh Schools of the Health Sciences

Related biology news :

1. Study finds monarch butterflies use medicinal plants to treat offspring for disease
2. UCLA-led research team finds that bacteria can stand up and walk
3. Long-extinct passenger pigeon finds a place in the family tree
4. Montana State team finds rare oasis of life on floor of Yellowstone Lake
5. Alcohol consumers are becoming the norm, UT Southwestern analysis finds
6. National study finds strong link between diabetes and air pollution
7. Study finds language barriers may play role in health care disparities
8. First study of its kind finds children with food allergies are often victims of bullying
9. UM School of Medicine Center for Celiac Research finds rate of celiac disease is growing
10. Pitt/Iowa team finds cellular structural molecule can be toxic: Makes pneumonia worse
11. Study finds possible persistence switch for tuberculosis
Post Your Comments:
(Date:6/7/2016)... 2016  Syngrafii Inc. and San Antonio Credit ... includes integrating Syngrafii,s patented LongPen™ eSignature "Wet" solution ... will result in greater convenience for SACU members ... maintaining existing document workflow and compliance requirements. ... Highlights: ...
(Date:6/2/2016)... 2, 2016 The Department of Transport ... the 44 million US Dollar project, for the , ... including Personalization, Enrolment, and IT Infrastructure , to ... production and implementation of Identity Management Solutions. Numerous renowned international ... Decatur was selected for the most compliant ...
(Date:6/2/2016)... June 2, 2016 Perimeter Surveillance ... Unmanned Systems, Physical Infrastructure, Support & Other Service  ... visiongain offers comprehensive analysis of the global ... will generate revenues of $17.98 billion in 2016. ... Inc, a leader in software and hardware technologies for ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... ... June 27, 2016 , ... ... on what they believe could be a new and helpful biomarker for malignant ... Click here to read it now. , Biomarkers are components in ...
(Date:6/27/2016)... PHILADELPHIA , June 27, 2016  Liquid ... today announced the funding of a Sponsored Research ... study circulating tumor cells (CTCs) from cancer patients.  ... changes in CTC levels correlate with clinical outcomes ... therapies. These data will then be employed to ...
(Date:6/24/2016)... , ... June 24, 2016 , ... While the majority ... as the Cary 5000 and the 6000i models are higher end machines that use ... height of the spectrophotometer’s light beam from the bottom of the cuvette holder. ...
(Date:6/23/2016)... 23, 2016   Boston Biomedical , an ... designed to target cancer stemness pathways, announced that ... Orphan Drug Designation from the U.S. Food and ... cancer, including gastroesophageal junction (GEJ) cancer. Napabucasin is ... inhibit cancer stemness pathways by targeting STAT3, and ...
Breaking Biology Technology: