Navigation Links
Studies on human genome variation provide insight into disease

The International HapMap Project was initiated with the primary goal of facilitating medical studies and understanding the genomic basis for human diseases. To coordinate with the journal Nature's publication describing the HapMap, the journal Genome Research is announcing a special issue entitled "Human Genome Variation," which is entirely devoted to studies using these data to provide insight into human biology and disease.

Predicting pregnancy success

Successful human reproduction and the maintenance of early pregnancy are dependent on a cluster of genes on chromosome 19 called the Luteinizing Hormone/Chorionic Gonadotropin Beta (LHB/CGB). During primate evolution, this cluster actively underwent numerous gene duplications and structural rearrangements, allowing the associated genes to acquire new biological functions.

In this month's issue of Genome Research, Dr. Maris Laan and her colleagues report their analysis of the LHB/CGB cluster in three human populations: European Estonians, African Mandenka, and Chinese Han. They demonstrate how gene conversion was critical for shaping the genetic diversity of this region in humans.

"This study paves the way for examining an individual's potential reproductive success based on sequence variants of the LHB/CGB genes," explains Laan. "We may be able to determine whether an individual is particularly susceptible to spontaneous abortions or reduced gonadal function, for example."

Maris Laan, Ph.D.
Research Professor, University of Tartu, Estonia
Phone: +372-53495258

X-ing out hereditary prostate cancer

According to the Prostate Cancer Foundation, one of every six American men develops prostate cancer, making it the most common form of non-skin cancer. Growing evidence suggests that there is a signific ant hereditary component to the disease, and one of the most strongly associated genomic regions lies on the X chromosome.

This X chromosomal region spans a cluster of five SPANX genes that are predominantly expressed in the testis and in certain tumors. In this month's issue of Genome Research, Dr. Vladimir Larionov and his colleagues examined the genetic architecture of the SPANX cluster and showed how the region exhibited dynamic deletions, duplications, and gene conversion events, some of which may have resulted in the development of mutations involved in prostate cancer susceptibility.

"Because of the strong similarity among genes in this region, we had to develop a new technique for our mutational analysis, which we call TAR cloning," explains Larionov. "Using this method, we isolated the SPANX region from 200 individuals by recombination in yeast."

Based on their results, the authors speculate that predisposition to prostate cancer ?at least in some individuals ?is determined by the specific architecture of the SPANX gene cluster on the X chromosome. "We're hoping to clarify which specific types of genomic rearrangements lead to prostate cancer susceptibility," says Larinov, "so that we can someday identify therapeutic targets for this disease."

Vladimir Larionov, Ph.D.
Head, Genome Structure and Function Section, National Cancer Institute
Phone: 301-496-7941

Genetic traffic in DiGeorge syndrome

One of the most common human genomic disorders, DiGeorge syndrome, occurs in one of every 2,000-4,000 live births and involves a deletion on chromosome 22. The deletion is mediated by rare repetitive sequences that flank genes crucial for proper development of the heart, face, and upper thorax.

Dr. Bernice Morrow and her colleagues describe in this month' s issue of Genome Research how they examined these flanking repetitive sequences for patterns of polymorphisms. "Our results show that there are intervals with more frequent traffic of genetic material ?regions with higher rates of gene conversion or recombination ?that are indicative of genomic instability," explains Morrow.

"With this knowledge in hand, we hope to screen our patients and identify the genomic mechanism underlying this important disease," says Morrow.

Bernice Morrow, Ph.D.
Professor, Albert Einstein College of Medicine
Phone: 718-430-4274

Looking for genes in all the right places

Geneticists rely on variation, or alterations in DNA sequence, for disease-association studies. Hereditary traits such as heart disease, arthritis, and Alzheimer's can be assigned to specific genomic regions based on their association with DNA markers.

The success of disease-association studies is dependent upon several characteristics of the DNA markers, including allelic frequency and genomic coverage. In some cases, a particular variant at one locus is perfectly associated with a specific variant at another locus; in other words, the two markers are "genetically indistinguishable."

Dr. Lon Cardon and his colleagues describe in this month's issue of Genome Research how these "genetically indistinguishable" polymorphisms can complicate the identification of disease-related genes. "Although they should pose few difficulties when they are located close together on the same chromosome, they often occur on different chromosomes, where it is quite another story," explains Cardon. When this is the case, true disease genes cannot be distinguished from their anonymous genetic 'twins.'

"Research in human genetic variation is rapidly moving towards realizing our aims of improving diagnosis of comm on diseases such as diabetes and heart disease," says Cardon, "but the genome is tricky; it won't reveal its secrets easily. The real disease-causing culprits can have many silent partners. We need to know the relationships of all these partners to focus on real disease mutations and to minimize attention on the innocent gene variants that colour the humanity of life."

Lon R. Cardon, Ph.D.
Professor of Bioinformatics, University of Oxford
Phone: +44-01865-287591


Source:Cold Spring Harbor Laboratory

Related biology news :

1. Studies reveal methods viruses use to sidestep immune system
2. Studies reveal how plague disables immune system, and how to exploit the process to make a vaccine
3. Studies clarify risk factors for mother-to-child transmission of hepatitis C virus
4. Studies suggest new brain protein may help in treating schizophrenia, insomnia and anxiety
5. Studies find general mechanism of cellular aging
6. Studies look at how genes affect antipsychotic drug response
7. Studies yield insight into the numerical brain
8. Studies force new view on biology of flavonoids
9. Novel technology detects human DNA mutations
10. Current human embryonic stem cell lines contaminated UCSD/Salk team finds
11. UWs Rosetta software to unlock secrets of many human proteins
Post Your Comments:

(Date:10/29/2015)... October 29, 2015 NXTD ... company focused on the growing mobile commerce market ... that StackCommerce, a leading marketplace to discover and ... Wocket® smart wallet on StackSocial for this holiday ... or the "Company"), a biometric authentication company focused ...
(Date:10/27/2015)... , October 27, 2015 ... Semantic Gaze Mapping technology (ASGM) automatically maps data from ... Tracking Glasses , so that they can be ... --> Munich, Germany , October 28-29, ... maps data from mobile eye tracking videos created with ...
(Date:10/26/2015)... ALTO, Calif. and LAS VEGAS ... Nok Nok Labs , an innovator in modern ... Alliance , today announced the launch of its latest ... first unified platform enabling organizations to use standards-based authentication ... The Nok Nok S3 Authentication Suite is ideal for ...
Breaking Biology News(10 mins):
(Date:11/24/2015)... ... November 24, 2015 , ... The Academy of Model Aeronautics (AMA), ... MultiGP, also known as Multirotor Grand Prix, to represent the First–Person View (FPV) racing ... AMA members have embraced this type of racing and several new model aviation pilots ...
(Date:11/24/2015)... 24, 2015  Tikcro Technologies Ltd. (OTCQB: TIKRF) today announced that its ... at 11:00 a.m. Israel time, at the law ... Allon Street, 36 th Floor, Tel Aviv, Israel ... and Izhak Tamir to the Board of Directors; ... directors; , approval of an amendment to certain terms of options ...
(Date:11/24/2015)... ... 24, 2015 , ... In harsh industrial processes, the safety ... sensors can represent a weak spot where leaking process media is a possible ... housings , which are designed to tolerate extreme process conditions. They combine rugged ...
(Date:11/24/2015)... /CNW Telbec/ - ProMetic Life Sciences Inc. (TSX: PLI) (OTCQX: ... Pierre Laurin , President and Chief Executive Officer of ProMetic, ... Jaffray 27 th Annual Healthcare Conference to be held ... st , at 8.50am (ET) and ProMetic,s ... day. The presentation will be available live via a webcast ...
Breaking Biology Technology: