Significance of DNA sequencing technology

With the rapid development of DNA sequencing methods, we not only know the whole genome sequence of human beings, but also know the sequences of wheat, rice, silkworm and many bacteria. At this time, finding out the biological significance represented by a sequence has become a new goal for scientists.

Through the analysis of the human genome sequence, scientists found that among the huge sequence of 3 billion pairs of nucleotides, only 1.5% was used to encode genes, a few played a role in regulating gene expression, and most of the rest were "junk DNA" with unknown functions. On the surface, the differences between people are so colorful and complicated, but at the DNA level, the gene coding sequence is only 0. 1% different. Many times, there is only one nucleotide difference between people in a sequence, which is named as single nucleotide polymorphism (SNPs) by scientists.

In the past, screening pathogenic genes among thousands of human genes was like looking for a needle in a haystack. Scientists need to get samples from patients in the same family before they can try to locate genes. For example, when searching for the pathogenic gene of Huntington's disease, many scientists struggled in a Huntington's disease family in Venezuela for more than ten years before they really caught it. Now, with the rapid sequencing technology and the powerful tools of SNPs, it will no longer be a dream to screen the susceptible population, identify the genes that cause or inhibit diseases, design and test the Qualcomm dosage of drugs and even personalized medical care.

Shenzhen huada gene research institute is one of the largest genome sequencing and research application centers in the world. BGI undertook the task of Human Genome Project 1%, and then participated in the international HAPmap project, completing the first genome sequencing in Asia and China, which was called "Yanhuang No.1".

Wellcome Trust is one of the largest biomedical funding institutions in the UK, with more than 50 research groups. In the past few years, they have implemented an ambitious plan-challenging polygenic diseases, such as bipolar disorder, coronary heart disease, Crohn's disease, rheumatoid arthritis, hypertension, type I diabetes and type II diabetes. By screening and analyzing the SNPs of 1.7 million British people, 24 loci related to the above seven diseases were found in the genome, and only 10 pathogenic genes were found and confirmed in the screening of type II diabetes. The existence of SNPs makes people realize that the human genome map is not unique. In fact, everyone has their own unique map. With the exponential growth of DNA sequencing speed, personal genome mapping service has gradually surfaced.

In 2006, the American X- Prize Foundation suspended 100000 USD, and rewarded the research team that could complete the whole genome sequencing of1000 people within10 days, and each person spent less than100000 USD. Previously, the National Institute of Human Genome also launched a plan to reduce the per capita cost of whole genome sequencing to below $65,438+$0,000.

At present, although no one has finally gone online, many companies have sniffed out the business opportunities-because most of the DNA sequences between people are consistent, it is also a kind of "quasi-personal genome service" to find out the differences in the customer's genome by screening SNP, especially to find out some disease-related sites.

In the competition in this field, "23 and I" company is undoubtedly the most popular. In addition to the gossip that "Anne Wokisky, one of the founders, is a talented woman from Yale who spans biology and finance" and "sergey brin, the wife of Google Technology President, joined", their products also won the top 50 inventions of the year selected by Time magazine in 2008 and ranked first.

At the end of 2007, "23 and I" officially launched a personalized genetic testing service at a price of $65,438+0,000 yuan. At that time, Warren Buffett and Rupert Murdoch, the media giant, both did tests. In September, 2008, the price of testing services plummeted to $399, finally allowing once unattainable personal genome testing to enter the homes of ordinary people.

Customers will receive a suite soon after ordering this service on the website of "23 and Me". Just spit 2.5 ml saliva in the sterile test tube provided by the kit, seal it and send it to the company. After 2~6 weeks, you will receive an email from the mailbox specified when ordering. According to the password in the letter, log on to the website of "23 and Me" and you will see all the results. For example, raw data containing genotype details, detailed reports of analysis results, and finally even references. According to "23 and Me", through this service, customers can know the future risks of cancer, Oates Harmo's disease, diabetes and other diseases.

In addition to "23 and Me" company, Iceland's deCODE company and California's Navigenics company have launched personal genetic testing services. However, in the face of these booming commercialization attempts, some scientists have raised their own concerns. Sometimes, diseases and genes are not in one-to-one correspondence with 100%. Many known disease markers only slightly increase the risk of diseases, but they will cause unnecessary worries.

Bioethicists are also concerned about the genetic discrimination caused by the popularization of personal genetic testing and the privacy leakage caused by improper protection of genetic data. Previously, in the United States, many insurance companies refused to provide medical insurance for some blacks on the grounds of carrying thalassemia genes. Fortunately, in May 2008, both the Senate and the House of Representatives of the United States overwhelmingly passed the Genetic Information Non-discrimination Act, which clearly stipulated that genetic tests showed that someone was susceptible to a certain disease, and insurance companies were not allowed to raise medical insurance premiums or refuse to provide insurance for them. Similarly, employers cannot use genetic information as a basis for recruitment, dismissal or promotion.

The rapid development of DNA sequencing technology is still helping scientists dig more secrets from DNA sequences, and the future is unpredictable. As Craig Venter, a well-known expert on human genome research and chief scientist of Celera Company in the United States, said, "The significance of decoding genome code is just like that in the era when electricity was just discovered. No one could imagine personal computers and the Internet."