<img loading="lazy" decoding="async" class="alignright size-full wp-image-2804" title="smoking" src="https://blog-api.23andme.com/wp-content/uploads/2009/02/smoking.jpg" alt="" width="350" height="260" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/02/smoking.jpg 350w, https://blogcms.23andme.com/wp-content/uploads/2009/02/smoking-300x223.jpg 300w" sizes="auto, (max-width: 350px) 100vw, 350px" />
For many common diseases, environment is far more important than genetics in determining whether a person will be affected. One of the best examples of this is lung cancer. Nearly 90% of the cases of this disease can be attributed to smoking.
<h6>Environmental Risk Factors</h6>
Today at the <a href="http://www.aaas.org/meetings/" target="_blank" rel="noopener">American Association for the Advancement of   Science meeting in Chicago</a>, however, Thorgeir Thorgeirsson of deCODE Genetics suggested that genetics may help foster a better understanding of the environmental risk factors for lung cancer.
Several studies published in April 2008, including one authored by Thorgeirsson, showed that a variation on chromosome 15 is associated with increased odds of lung cancer.   Thorgeirsson’s group also showed that this same variation is associated with increased smoking — about one cigarette per day per copy of the riskier version
<h6>Does Genetics Influence How Much You Smoke?</h6>
Together these findings raise an important question:   does this variation increase the odds of cancer because it increases the amount a person smokes?
According to Thorgeirsson, there should be only a 5% increase in the odds of developing lung cancer based on the increase in smoking associated with the genetic variation. But the data indicate that each copy of the riskier version actually increases odds of the disease by about 30%.
This, Thorgeirsson suggested, could mean that the variation is associated not just with smoking quantity, but also with another behavior, such as how deeply a smoker inhales or how far down he usually smokes his cigarettes.   He noted a recent study published in <a href="https://www.ncbi.nlm.nih.gov/pubmed/19010884?ordinalpos=3&amp;itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum" target="_blank" rel="noopener">Cancer Research</a> that found that, compared to smokers without the genetic variation, those with it take in more nicotine and carcinogens with every cigarette.
Another possibility is that the variation has a dual effect.   It could increase not just smoking quantity, but also the vulnerability of a person&#8217;s cells to the harmful effects of the smoke.
Although there’s still much work to be done in order to fully understand the effects of this particular genetic variation, the results so far hint at the fact that genes and environment may for more interconnected than previously appreciated.

23andMe Blog

23andMe Blog Team

How A Person Smokes Might Affect Lung Cancer Risk

<img loading="lazy" decoding="async" class="alignright size-full wp-image-421" title="Neanderthal" src="https://blog-api.23andme.com/wp-content/uploads/2008/07/neanderthaler2.jpg" alt="" width="400" height="266" srcset="https://blogcms.23andme.com/wp-content/uploads/2008/07/neanderthaler2.jpg 400w, https://blogcms.23andme.com/wp-content/uploads/2008/07/neanderthaler2-300x200.jpg 300w" sizes="auto, (max-width: 400px) 100vw, 400px" />
First came the Human Genome Project when, in the year 2000, an international team of scientists began mapping all 23 pairs of our chromosomes.   Then in 2005, the Chimpanzee Genome Project took off, attempting to do the same for the 24 chromosomes of our species&#8217; closest living relative.   With intimate knowledge of the genetic make-up of both species, scientists could decipher the evolutionary changes that took place in the 7 million years since the time of our last shared ancestor.
Now, a joint research team led by Svante PÃ¤Ã¤bo of the Max Planck Institute for Evolutionary Anthropology has gone one step further by mapping the complete genome of our nearest extinct relative. PÃ¤Ã¤bo and his colleagues announced the completion of a draft Neanderthal genome sequence today in Chicago at the annual meeting of the <a href="http://www.aaas.org" target="_blank" rel="noopener noreferrer">American Association for the Advancement of Science</a>.

Neanderthals &#8211; our short, stocky, evolutionary cousins &#8211; lived in Europe during the harshest conditions of the Ice Age.   They survived in regions where few other animals could.   Neanderthals first came on the scene over 350,000 years ago, but seemed to dwindle in numbers with the arrival of humans about 40,000 years ago.   By 25,000 years ago they had disappeared completely.
But there are still many questions surrounding the fate of the Neanderthals.   While most scientists argue that Neanderthals were simply out-competed by the arriving humans, some believe that Neanderthals and early humans may have interbred, and that many modern Europeans have Neanderthal DNA interspersed throughout their genome.   Others believe that Neanderthals and early humans were in fact members of the same species, and should therefore have very similar DNA.
Solving the mystery has been no easy task. Because the archaeological samples available to PÃ¤Ã¤bo and his colleagues – three bone fragments from a cave in Croatia – are 30,000 years old, what little DNA they contain has been broken down into short fragments of just a few hundred base pairs each – a fraction of the billions that make up a complete genome.
Initially, the researchers focused on the mitochondrial DNA, because it is so prevalent in each cell.   When comparing the mitochondrial DNA of Neanderthals to that of modern humans, they found substantial differences between the two &#8211; indicating that humans and Neanderthals could not have been members of the same species.
However, the mitochondrial DNA represents only a fraction of the entire Neanderthal genome.   If we want to know the real genetic differences between humans and Neanderthals, then we&#8217;ll have to examine not just a small fraction, but the whole genome – all 46 chromosomes of it.
Working with 454 Life Sciences Corp of Branford, Conn., PÃ¤Ã¤bo and his team have devised a way to extract large amounts of nuclear DNA &#8211; DNA from the 23 pairs of chromosomes inside each cell &#8211; from prehistoric mammals, including Neanderthals.   All told, the two research teams have so far sequenced over 3 billion bases of Neanderthal nuclear DNA, constructing a &#8216;rough draft&#8217; of the entire Neanderthal genome.
The sheer difficulty in completing such a task cannot be underestimated.   As soon as these Neanderthals died, tens of thousands of years ago, the DNA inside each cell began breaking down.   Up until recently, extracting the few remaining bits of DNA from fossils like these was virtually impossible.   Now, as PÃ¤Ã¤bo and others comb through the Neanderthal genome, we can embark on new chapter in the continuing saga surrounding the relationship between humans and Neanderthals.

Researchers Announce Draft Version of Complete Neanderthal Genome

<img loading="lazy" decoding="async" class="alignright size-full wp-image-2780" title="origin_of_species_title_page" src="https://blog-api.23andme.com/wp-content/uploads/2009/02/origin_of_species_title_page.jpg" alt="" width="174" height="300" />
Biology has changed a lot over the past 150 years. Scientists have discovered entirely new forms of life, deciphered the molecular code of heredity and observed the machinery of life on the smallest dimensions. And through it all, one scientific theory has stood the test of time.
<h6>The Origin of Species</h6>
New discoveries in genomics, medicine, developmental biology, and countless other fields could have derailed the the theory of evolution. But the core principles of evolutionary theory, proposed by Charles Darwin 150 years ago, have remained among the strongest explanations of the natural world ever published.
In honor of Darwin Day 2009, which celebrates the 200th anniversary of Charles Darwin’s birth and the 150th anniversary of the publication of his seminal work, On the Origin of Species, we’d like to take a look at how evolution has itself ‘evolved’ over the decades – how new advances in science and technology have both reinforced Darwin’s original idea and given us insight into the inner workings of the theory that explains so much about the world in which we live.
In 1859, the phrase ‘evolution by natural selection’ was already beginning to make the rounds among the scientific elite in Europe and in America.   This was the year Darwin published On the Origin of Species, and his ideas about how species change over time were causing heated debate among the experts.   
<h6>Theory of Evolution</h6>
But Darwin didn’t invent the idea of ‘evolution’ (that is, the idea that species change over time).   What he brought to the table was an explanation of how species change, a process Darwin called ‘natural selection.’   On his famous journey to the Galapagos Islands 25 years earlier, Darwin had witnessed unique variation in hundreds of species.   
As he pored over his notes for the next two decades, Darwin pieced together the notion that species must adapt to environmental pressures (like changes in climate or a volcanic eruption), in order to survive.   If they did not adapt to these pressures, then they may not survive.   It was natural selection, Darwin argued, that was the basis for the vast differences we see in plant and animal species across the globe.
But there was a lot that Darwin did not know when he published his ideas of evolution.
<h6>Natural Selection</h6>
He did not know, for instance, how changes in a species&#8217; appearance (a longer beak, a bigger shell, or a thicker coat of fur) are passed down from generation to generation.
The idea of discrete units – ‘genes’ that are passed down from parents to children – had not even occurred to Darwin, nor to most of the other scientists of the time.   Even when, in 1866, an Austrian monk named Gregor Mendel reported his ideas on patterns of inheritance in pea plants in the obscure Proceedings of the Natural History Society of BrÃ¼nn, few took notice.
<h6>Genetics</h6>
In fact, the word ‘genetics’ wasn’t coined until 1905, by biologist William Bateson. Bateson, who is sometimes credited with ‘rediscovering’ the lost works of Mendel, helped to usher in a new wave of research and discovery – this time looking at how species differ from each other at the molecular, or genetic, level.   Bateson&#8217;s push for the use of genetics in evolutionary research reached fruition in 1952, when Cambridge scientists James Watson and Francis Crick decoded the structure of DNA.
Soon others discovered how specific genes are passed down from generation to generation, and how changes in our genetic code are connected to changes in species.   As each new genetic discovery allowed us to better understand the natural world at a microsopic level, Darwin&#8217;s theory of evolution by natural selection was continually reinforced.
The evolution of our species, Homo sapiens, forms the basis for virtually everything we can learn from 23andMe&#8217;s <a href="https://23andme.com" target="_blank" rel="noopener">Personal Genome ServiceTM</a>.   The signature of millions of years of evolution is present in every person&#8217;s genome, and often in our physiology, rendering some of us resistant to malaria, others unable to digest milk, and even causing some to have lower risks of cancer or other diseases.   As advances in science and technology continue to bring us more information hidden within our genes, we can be thankful that 150 years ago, an amateur naturalist from Shrewsbury, England, boarded a ship bound for South America and began piecing together the evolutionary story of not just our species but of all life on earth.

The Evolution of a Theory:  Darwin and Evolution 150 Year Later

<img loading="lazy" decoding="async" class="alignright size-full wp-image-2776" title="british_two_pound_coin_2009_charles_darwin" src="https://blog-api.23andme.com/wp-content/uploads/2009/02/british_two_pound_coin_2009_charles_darwin.png" alt="" width="202" height="202" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/02/british_two_pound_coin_2009_charles_darwin.png 202w, https://blogcms.23andme.com/wp-content/uploads/2009/02/british_two_pound_coin_2009_charles_darwin-150x150.png 150w" sizes="auto, (max-width: 202px) 100vw, 202px" />
Put on your party hat.   Tomorrow, in universities and public auditoriums, at festivals and museums, people around the world will be celebrating the life and works of one of the most influential scientific minds in history:   Charles Darwin.   February 12th is Darwin&#8217;s 200th birthday, and this year &#8211; 2009 &#8211; also marks 150 years since the publication of his most famous work, On the Origin of Species.   Darwin&#8217;s works have &#8211; time and again &#8211; played a key role in advancing scientific thought in such fields as biology, genetics, biochemistry, and paleontology (just to name a few!).
The life and works of Darwin have been deemed so important by scientists from around the world that hundreds of museums, organizations, and scientific societies have decided to celebrate his birthday and his research.   Here are some of the notable events planned in celebration of Darwin, his life, and his contributions to the field of science.
National Academy of Sciences: Two Centuries of Darwin
<a id="six." title="The National Academy of Sciences" href="http://www.nasonline.org/site/PageServer" target="_blank" rel="noopener">The National Academy of Sciences</a> of the United States, a prestigious scientific honors society that provides advice to the nation&#8217;s leaders on all topics related to science and technology, has revamped its <a id="w47q" title="resources on evolution" href="http://nationalacademies.org/evolution/index.html" target="_blank" rel="noopener">resources on evolution</a> in honor of Darwin Day.   In addition, it is hosting a series of events to honor Darwin and his scientific works.   The Academy is sponsoring a lecture series centered around the importance of evolution in advancing medical research. The lecture series will be held in Washington, D.C., but it will be streamed online to anyone who wishes to learn more about this fascinating topic.
<h6>Celebrations on the Newsstands</h6>
Many major scientific publications, including Science , <a id="tx1v" title="Nature" href="https://www.nature.com/news/specials/darwin/index.html" target="_blank" rel="noopener">Nature</a> , <a id="np.n" title="National Geographic" href="http://ngm.nationalgeographic.com/featurehub" target="_blank" rel="noopener">National Geographic</a>, and The Lancet, have released special issues in honor of Darwin&#8217;s work.   Science has also begun publishing a blog, <a id="p_1i" title="Origins" href="http://blogs.sciencemag.org/origins/" target="_blank" rel="noopener">Origins</a>, which tackles some of the most fascinating aspects of modern evolutionary theory.   Each of these journals has chosen a specific aspect of evolutionary theory to discuss, giving us deeper insight into the mind of Darwin and how scientific research has progressed over the last 150 years.University of Cambridge:   Darwin 2009
Darwin&#8217;s alma mater &#8211; Cambridge University &#8211; is particularly excited about Darwin Day.   The institution has planned several days of activities throughout the town and university, though we&#8217;ll have to wait a bit longer to celebrate.   Cambridge is organizing the bulk of the festivities for July, where &#8211; over five days &#8211; the town will be transformed into a celebration of scientific thought.   Organizers and volunteers have planned dozens of lectures, film showings, tours, exhibitions, and workshops.   Such well known scientific personalities as Richard Dawkins, Richard Leakey, and Sir David Attenborough will be presenting their take on the importance of Darwin and the importance of evolution.   It is sure to be an exciting festival &#8211; so start booking flights now!
There are in fact several hundred Darwin Day-related events going on during all of 2009, with many beginning this week.   Be sure to check the official list of Darwin Day 2009 activities in your area.

Bicentennial Birthday:  Darwin Day 2009!

<img loading="lazy" decoding="async" class="alignright size-full wp-image-2759" title="heartman" src="https://blog-api.23andme.com/wp-content/uploads/2009/02/heartman.jpg" alt="" width="350" height="260" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/02/heartman.jpg 350w, https://blogcms.23andme.com/wp-content/uploads/2009/02/heartman-300x223.jpg 300w" sizes="auto, (max-width: 350px) 100vw, 350px" />
Lifestyle factors such as smoking or a high-fat diet are well-established contributors to heart attack risk, because they encourage the accumulation of sticky plaques inside the arteries that supply the heart with oxygen- and nutrient-rich blood.
Though genetics plays an almost equal role in the accumulation of plaques in the coronary arteries, the specific genes involved in the process are largely unknown.   Only one region of DNA on chromosome 9 has consistently been linked to heart disease.
(23andMe customers can learn more in the Heart Attack Research Report.)
Now five studies, published online yesterday in the journal Nature Genetics, have identified a bumper crop of genetic variations associated with coronary artery disease (the build up of plaque) and heart attack.   Although more work will be needed to confirm these associations and figure out exactly how they affect risk, these results are a major step forward in understanding the biology of heart disease. Eventually the variations identified in these and future studies may be useful for prediction, prevention or treatment of coronary artery disease and heart attack.
Four of the studies looked at the effects of individual SNPs on coronary artery disease or heart attack. 23andMe customers can check their data for many of these using the information at the end of this post. The <a href="https://dx.doi.org/10.1038/ng.314" target="_blank" rel="noopener">fifth study</a> looked at the effect of a combination of four SNPs.   23andMe cannot currently provide customers with the type of data described in this study.
Note: In each table, “Effect” refers to the increase in odds for each copy of the risk version compared to two copies of the non-risk version of the SNP.
Study: <a href="https://dx.doi.org/10.1038/ng.327" target="_blank" rel="noopener">Myocardial Infarction Genetics Consortium</a> 
Early-onset heart attack (men 50 years old or younger, women 60 years old or younger) 
Cases: More than 12,000 
Controls: More than 12,000 
Populations studied: European ancestry; United States, Sweden, Finland, Spain, Italy, U.K., Germany, Ireland and Iceland

Five New Studies Identify Genetic Variations Associated with Coronary Artery Disease and Heart Attack

<img loading="lazy" decoding="async" class="alignright size-full wp-image-2751" title="thyroid_papillary_carcinoma_histopathology_4" src="https://blog-api.23andme.com/wp-content/uploads/2009/02/thyroid_papillary_carcinoma_histopathology_4.jpg" alt="" width="350" height="263" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/02/thyroid_papillary_carcinoma_histopathology_4.jpg 350w, https://blogcms.23andme.com/wp-content/uploads/2009/02/thyroid_papillary_carcinoma_histopathology_4-300x225.jpg 300w" sizes="auto, (max-width: 350px) 100vw, 350px" />
Each year in the United States, about five out of every 100,000 men and 14 out of every 100,000 women develop thyroid cancer. &nbsp; The number of diagnosed cases has been increasing over the past few decades, but the number of deaths due to the disease — about 1,500 per year — has remained the same. &nbsp; Experts have suggested that this means the number of people affected by the disease is not actually changing, just the number found by physicians.
Studies have shown that genetics plays a larger role in thyroid cancer compared to other malignancies, but not much is known about the specific genes or variations that might be involved. &nbsp; Now, a study being published online today by the journal <a href="https://dx.doi.org/10.1038/ng.339" target="_blank" rel="noopener">Nature Genetics</a> has identified two variations that together can increase the risk of thyroid cancer more than five-fold.
In a combined analysis that compared more than 960 subjects with thyroid cancer from Iceland, Spain and the United States to more than 38,000 controls, Julius Gudmundsson and colleagues found that each A at SNP rs965513 increased the odds of the disease by 1.75 times. Each T* at rs944289 increased the odds of thyroid cancer by 1.37 times.
According to the authors, about 3.7% of the population with European ancestry has the riskier version at both copies of both SNPs. &nbsp; These people are estimated to have 5.7 times greater odds of developing thyroid cancer compared to people who carry no risky versions of either SNP.
The riskier versions of both SNPs were also associated with decreased blood levels of thyroid stimulating hormone, a key regulator of thyroid function that is secreted by the pituitary gland. &nbsp; The A version of rs965513 was also associated with changes in the blood levels, of T3 and T4, two hormones made by the thyroid itself.
“Compared to the common susceptibility variants recently discovered for complex diseases, the relative risks associated with the variants reported here are quite high….Furthermore, we have demonstrated that these variants influence crucial players in the thyroid hormonal pathway. &nbsp; These variants are therefore likely to be among the most important determinants of genetic susceptibility to thyroid cancer,” the authors conclude.
* The original post contained an error, identifying the C version of rs944289 as the version that is associated with increased odds of thyroid cancer. &nbsp; In fact, it is the T version of this SNP that increases odds by 1.37 times. &nbsp; We apologize for this mistake, and thank the Blog reader who brought it to our attention.

Two Gene Variations Linked to Thyroid Cancer

<img loading="lazy" decoding="async" class="alignright size-full wp-image-2744" title="sun" src="https://blog-api.23andme.com/wp-content/uploads/2009/02/sun.jpeg" alt="" width="350" height="260" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/02/sun.jpeg 350w, https://blogcms.23andme.com/wp-content/uploads/2009/02/sun-300x223.jpeg 300w" sizes="auto, (max-width: 350px) 100vw, 350px" />
Multiple sclerosis (MS) is a common inflammatory disease that leads to the destruction of the insulating coating that surrounds nerves in the brain and spinal cord. Without this insulation, the electrical impulses the nerves are supposed to carry between the brain and rest of the body get confused or lost along the way, leading to a loss of control of a variety of bodily functions.
Genetic factors, especially variants in immune system genes, are known to play a part in MS.   But environment is important too.   Most striking is the influence of geography.   Increasing distance from the equator is associated with higher prevalence of MS.   Sunlight, and specifically its role in generating active vitamin D in the body, has been proposed to be the reason for this effect. The exact role of vitamin D in the disease, however, has not been shown.
New research, published online today in the journal <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1000369" target="_blank" rel="noopener">PLoS Genetics</a>, shows a direct connection between vitamin D and the strongest genetic risk factor for MS found so far. These findings suggest that simply taking a supplement during pregnancy and childhood could prevent this disabling disease from developing.
In laboratory experiments, Sreeram Ramagopalan and colleagues from the University of Oxford and the University of British Columbia showed that a variant of the HLA-DRB1 gene called HLA-DRB1*1501 is turned on by vitamin D.   Other versions of the HLA-DRB1 gene were not responsive to the vitamin.   The researchers did not address what might be responsible for turning these versions on.
In people with European ancestry, each copy of the HLA-DRB1*1501 variant increases the odds of developing MS by about two times compared to someone with no copies. About 40% of this population has at least one copy.
(23andMe customers can check their data for HLA-DRB1*1501 in the Multiple Sclerosis research report.)
The researchers think that in people with the HLA-DRB1*1501 variant, vitamin D deficiency prevents the gene from being turned on during development in utero and in the early years of childhood, when it and other genes like it are involved in training the immune system to distinguish between the body’s own tissues and foreign invaders such as bacteria and viruses.   Immune cells that have failed this basic training but nonetheless been released into the circulation are thought to be behind the nerve cell destruction seen in MS.
According to the authors, the idea that it’s not just vitamin D, but when you get it, is supported by data on MS among people who have migrated from sunny low-risk regions such as the Caribbean to regions with low sunlight such as the U.K., where the risk for the disease is much higher.
“Immigrants who migrate before adolescence acquire the risk of their new country, while those who migrate after retain the risk of their home country,” the authors write.
“This study provides more direct support for the already strong epidemiological evidence implicating sunlight and vitamin D in the determination of MS risk.   Given that a high frequency of vitamin D insufficiency in the general population has been observed, our data support the case for supplementation during critical time periods to reduce the prevalence of this devastating disease,” the authors conclude.

Taking Vitamin D Supplements In Childhood May Prevent Multiple Sclerosis Later

<img loading="lazy" decoding="async" class="size-full wp-image-1715" title="altman" src="https://blog-api.23andme.com/wp-content/uploads/2008/10/altman.jpg" alt="Russ Altman" width="130" height="170" />Russ Altman 
We&#8217;re pleased to announce that 23andMe Science Advisory Board member Russ Altman has won the Nature Network 2008 Science Blogging Challenge for his blog, &#8220;Building confidence.&#8221;
Russ was commended for his insights about pharmacogenomics, science funding, <a href="http://rbaltman.wordpress.com/2008/10/08/genotyping-cost-is-asymptoting-to-free/" target="_blank" rel="noopener noreferrer">the implications of rapidly decreasing genotyping costs</a> and other topics. His account of how cool it is to have access to your genetic data (&#8220;One of my first post-genomic moments&#8221;) was also selected by the judges to be part of an anthology of last year&#8217;s best science blogging.

The people who created the prize run an online social network for scientists that is part of the Nature Publishing Group, which also sponsors the annual Science Foo Camp (SciFoo) at Google headquarters in Mountain View, Calif. Russ won a free trip to this year&#8217;s SciFoo camp (But since he lives just a few miles away the money that would have gone to his travel expenses will be used to help deserving attendees who have farther to travel!).
Congratulations, Russ. Keep blogging.

23andMe Science Advisor Wins Science Blogging Challenge

Latest Posts — Page 197

How A Person Smokes Might Affect Lung Cancer Risk

Researchers Announce Draft Version of Complete Neanderthal Genome

The Evolution of a Theory: Darwin and Evolution 150 Year Later

Bicentennial Birthday: Darwin Day 2009!

Five New Studies Identify Genetic Variations Associated with Coronary Artery Disease and Heart Attack

Two Gene Variations Linked to Thyroid Cancer

Taking Vitamin D Supplements In Childhood May Prevent Multiple Sclerosis Later

23andMe Science Advisor Wins Science Blogging Challenge

Tonight on Frontline: My Father, My Brother, and Me

Stay in the know.