The elementary concept is that the father’s role in making babies is to only contribute the sperm, and the mother does all the work. That after fertilization, the development of the resulting embryo is at the mercy of the mother’s egg cytoplasm that received it.

Well, recent studies show that dad’s sperm contains a set of instructions that make certain the embryo develops properly, and specifically that his genes get turned on at the right time.

But let’s do a short tutorial first…

Each chromosome is really just a single long DNA molecule, that can stretch out to an average 1 meter long. Those 23 long strands of human DNA must be packaged and coiled into a tiny nucleus. The proteins responsible for packaging them are called histones. Histone molecules repeatedly fold and coil the DNA strand into the more visible (through microscope) chromosome. Histones also regulate which portions of the DNA can unravel so that genes can be replicated and expressed at the right timing for the embryo to develop normally. Histones are also highly conserved in evolution, meaning they are identical from one organism to another and likely have the same functions in all organisms.

A new study published at Nature found that specially-modified histones are strategically found in different areas of the sperm chromatin. In some areas, the father’s genes that need to be turned on early in an embryo’s development are marked with modified histones different from those genes that are needed later in the development.

What’s the implication for this finding? Bradley R. Cairns, senior researcher of the team, remarked that a man’s age and lifestyle could affect the sperm chromatin in such a way that impacts fertility or development of the embryo. Cairns also expressed hope that a diagnostic test could be developed based on his results that will help couples with fertility issues.

Read more about the study in “Sperm’s Genes Packaged with Instructions for Development”.

Image: Newscom

For the first time, US researchers have decoded all the genes of a woman who died of myeloid leukemia, and they found 10 mutations that contributed to the development of her cancer.

This finding is significant on several fronts. It’s the first time that a cancer genome has been sequenced. The scientists took samples of both cancer and normal skin cells from the same woman, and sequenced the DNA on both samples. Previous to this, the focus was on select regions of the genome, called candidate regions, suspected of carrying genes that cause or contribute to cancer.

The study also found that 8 of the 10 mutations have never been suspected as contributing to the disease. The researchers found them on every cancer cell and none in the normal samples, which suggests that these mutations play as-yet unknown roles in skin cancer.

The research is focused on skin cancer, but scientists are enthusiastic about finding similar or the same genes in other types of cancers.

At her request, the woman’s identity is kept secret, but this is also the first time that a woman’s genome has been sequenced. Previous to her, only James Watson and Craig Venter’s DNA have been decoded. 

Enlarged hearts are found often, but not exclusively, in those who are obese, have diabetes or high blood pressure. People with none of these underlying problems can be affected, as can elite athletes.  For example, a post-mortem diagnosed the problem in Cameroon football midfielder Marc-Vivien Foe, who died in 2003 after collapsing during an international match in France. Elite runner Olympic hopeful Ryan Shay died of complications involving an enlarged heart - the very condition that made him a great runner.

An international  research team headed up by Imperial College, UK say they have for the first time linked enlarged hearts with a gene, osteoglycin (Ogn).

Work carried out on rodents and some 30 humans indicated that Ogn - which has never before been linked with heart function - regulated the growth of the heart’s main pumping chamber, its left ventricle.  When this gene behaves abnormally the heart can become enlarged, putting the person at an increased risk of common heart diseases and heart attacks.

For further information, click on:

http://www3.imperial.ac.uk/newsandeventspggrp/imperialcollege/newssummary/news_29-4-2008-13-31-10

Elaine Warburton  www.geneticsandhealth.com

At last one for the girls!

 … Geneticists at Leiden University Medical Centre (LUMC) are the first to determine the DNA sequence of a woman. She is also the first European whose DNA sequence has been determined

The DNA is that of Dutch scientist Dr Marjolein Kriek, a clinical geneticist at LUMC. “If anyone could properly consider the ramifications of knowing his or her sequence, it is a clinical geneticist,”says professor Gert-Jan B van Ommen, leader of the LUMC team. 

Now we have  a new ‘Watson and Kriek’ to compare genetic diversity!

Elaine Warburton  www.geneticsandhealth.com

 (Tasmanian Tiger - photo credit www.bbc.co.uk/news)

Using transgenic mice, Australian and American researchers have shown that they can “resurrect” a snippet of DNA from the genome of an extinct animal — the Tasmanian tiger — and test its biological function in a living animal.   The last Tasmanian Tiger died in an Australian zoo in 1936 having been hunted to extinction.

Dr Andrew Pask, of the Department of Zoology at Melbourne University, who led the research, said it was the first time that DNA from an extinct species had been used to carry out a function in a living organism.

“As more and more species of animals become extinct, we are continuing to lose critical knowledge of gene function and its potential,” he said.  “Up until now we have only been able to examine gene sequences from extinct animals. This research was developed to go one step further to examine extinct gene function in a whole organism.”

The team extracted DNA from some of these specimens, and injected a gene involved in cartilage formation into developing mouse embryos.  The DNA functioned in a similar way to the equivalent gene in mice, giving information about the genetic make-up of the extinct marsupial.

“At a time when extinction rates are increasing at an alarming rate, especially of mammals, this research discovery is critical,”said Professor Marilyn Renfree, also of the University of Melbourne’s Department of Zoology.

“For those species that have already become extinct, our method shows that access to their genetic biodiversity may not be completely lost.”

Elaine Warburton  www.geneticsandhealth.com

GNA 

(Source: John Chaput, University of Arizona)

Nanotechnology researchers are continually on the lookout for new building blocks to push innovation and discovery to scales much smaller than the tiniest speck of dust.  At present DNA nanotechnology researchers are basically limited by what they can buy off the shelf.

In the Biodesign Institute at Arizona State University, researchers led by John Chaput, are building synthetic molecules that assemble like DNA, but have additional properties not found in natural DNA.  It’s called GNA. In the case of GNA, the sugar is the only difference with DNA. The five carbon sugar commonly found in DNA, called deoxyribose, is substituted by glycerol, which contains just three carbon atoms.

In nature, many molecules important to life like DNA and proteins, have evolved to exist only as right-handed. The GNA structures, unlike DNA, turn out to be ‘enantiomeric’ molecules, which in chemical terms means both left and right-handed. The ability to make mirror image structures opens up new possibilities for making nanostructures. The research team also found a number of physical and chemical properties that were unique to GNA, including having a higher tolerance to heat than DNA nanostructures.

Now, with a new material in hand, which John Chaput dubs ‘unnatural nucleic acid nanostructures,’ the group hopes to explore the limits on the topology and types of structure they can make.

http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/2008/130/i18/abs/ja800079j.html

Elaine Warburton  www.geneticsandhealth.com

Osteoporosis 

(Image source: www.soylabs.com) 

An extensive genome-wide search has been undertaken to find the genes linked to osteoporosis and fracture. Five regions of interest have been identified that appear to warrant further scientific investigation.

The Garvan Institute for Medical Research collaborated with the Icelandic genetics company, deCode, in a project that looked at 1500 women from Garvan’s Dubbo Osteoporosis Epidemiology Study as well as more than 12,000 women from Iceland and Denmark.

The collaborative study examined more than 300,000 such markers and found 12 that were linked to bone mineral density and 6 linked to fragility fractures. Some of these SNPs are close to genes that are already known to be associated with osteoporosis.

The next step will be identifying what those genes are and how they might contribute to scientists understanding of osteoporosis and its prevention.

http://www.decode.com/News/2008_04_29.php

Elaine Warburton  www.geneticsandhealth.com
 

KQED Public Broadcasting in San Francisco recently did a radio story about the UC San Francisco Canine Behavioral Genetics Project run in collaboration with the University of Pennsylvania. The aims of the project are:

1. To explore the relationship between genes and behavior, both normal and abnormal, in domestic dogs.

2. To assess the amount and nature of genetic diversity in domestic dogs, both within and between breeds. 

Melanie Chang of the CBG project

Anyone wishing to send in their dog’s DNA can visit the site:

http://www.k9behavioralgenetics.com/ 

Dog DNA samples waiting to be processed at the CBG project 

However, it is often said dogs and their owners resemble each other. Now, researchers within this project are looking for those connections on a whole new level. They’re searching for the genes that cause common psychiatric problems in humans - by looking at the DNA of dogs. Have a listen to this very interesting broadcast:

http://www.kqed.org/quest/radio/view/836

Elaine Warburton  www.geneticsandhealth.com

(Image courtesy of CIMA http://www.cima.es/areas1_neuro/areas1_neuro_english.html) 

Data from one of the first genome-wide association studies (GWAS), which focused on Parkinson’s diseases and was funded in part by The Michael J. Fox Foundation for Parkinson’s Research (MJFF), is now being made available to researchers through the National Human Genome Research Institute (NHGRI) and the National Center for Biotechnology Information (NCBI), both of the National Institutes of Health (NIH). NHGRI hopes to speed up research by making previously unavailable GWAS data sets publicly available to the research community.

The study, conducted by researchers at Mayo Clinic in Rochester, Minn., in collaboration with scientists at Perlegen Sciences, Inc., in Mountain View, Calif., was the first genome-wide association study applied to Parkinson’s disease. It was funded under MJFF’s Linked Efforts to Accelerate Parkinson’s Solutions (LEAPS) initiative.

“The Michael J. Fox Foundation is committed to spurring innovation by creating every possible opportunity for researchers to collaborate and share their knowledge,” said Katie Hood, chief executive officer of The Michael J. Fox Foundation.

Researchers interested in accessing the Mayo-Perlegen LEAPS Collaboration study dataset should go to dbGaP’s Web site and complete a request for access to the individual-level data at http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?id=phs000048. Information on data access request procedures is available through the dbGaP “controlled access” Web page, at http://dbgap.ncbi.nlm.nih.gov/aa/wga.cgi?login=&page=login.

Elaine Warburton  www.geneticsandhealth.com

HIV-2 Virus. Reference: http://www.csend.hu/magazin/0102/hiv2.jpg

A team of researchers at the University of Alberta has discovered a gene that is able to block HIV, and in turn prevent the onset of AIDS.  Stephen Barr, a molecular virologist in the Department of Medical Microbiology and Immunology, says his team has identified a gene called TRIM22 that can block HIV infection in a cell culture by preventing the assembly of the virus.

Stephen Barr (Courtesy of University of Alberta, Canada)

Barr says “interestingly, when we prevent cells from turning on TRIM22, the normal interferon response (a natural defense produced by our cells to fight infection by viruses such as HIV) is useless at blocking HIV infection. This means TRIM22 is an essential part of our body’s ability to fight off HIV.”

Barr’s team finds the results very exciting because it shows our bodies have a gene that is capable of stopping the spread of HIV. They are now trying to figure out why this gene does not work in people infected with HIV and if there is a way to turn this gene on in those individuals. “We hope that our research will lead to the design of new drugs and/or vaccines that can halt the person-to-person transmission of HIV and the spread of the virus in the body, thereby blocking the onset of AIDS.” 
 

For further information, click on

http://www.expressnews.ualberta.ca/article.cfm?id=9131

Elaine Warburton www.geneticsandhealth.com