Photo:366 • 149 • Last day before final exam By Pragmagraphr
Studies in Drosophila Provide a Key to Vertebrate Development
The fruitfly Drosophila melanogaster (Figure 1-48) has been in use as a model genetic organism for longer than any other; in fact, the foundations of classical genetics were built to a large extent on studies of this insect. Over 80 years ago, it provided, for example, definitive proof that genes—the abstract units of hereditary information—are carried on chromosomes, concrete physical objects whose behavior had been closely followed in the eucaryotic cell with the light microscope, but whose function was at first unknown. The proof depended on one of the many features that make Drosophila peculiarly convenient for genetics—the giant chromosomes, with characteristic banded appearance, that are visible in some of its cells (Figure 1-49). Specific changes in the hereditary information, manifest in families of mutant flies, were found to correlate exactly with the loss or alteration of specific giant-chromosome bands.
In more recent times, Drosophila, more than any other organism, has shown us how to trace the chain of cause and effect from the genetic instructions encoded in the chromosomal DNA to the structure of the adult multicellular body. Drosophila mutants with body parts strangely misplaced or mispatterned provided the key to the identification and characterization of the genes required to make a properly structured body, with gut, limbs, eyes, and all the other parts in their correct places. Once these Drosophila genes were sequenced, the genomes of vertebrates could be scanned for homologs. These were found, and their functions in vertebrates were then tested by analyzing mice in which the genes had been mutated. The results, as we see later in the book, reveal an astonishing degree of similarity in the molecular mechanisms of insect and vertebrate development.
The majority of all named species of living organisms are insects. Even if Drosophila had nothing in common with vertebrates, but only with insects, it would still be an important model organism. But if understanding the molecular genetics of vertebrates is the goal, why not simply tackle the problem head-on? Why sidle up to it obliquely, through studies in Drosophila?
Drosophila requires only 9 days to progress from a fertilized egg to an adult; it is vastly easier and cheaper to breed than any vertebrate, and its genome is much smaller—about 170 million nucleotide pairs, compared with 3200 million for a human. This codes for about 14,000 proteins, and mutants can now be obtained for essentially any gene. But there is also another, deeper reason why genetic mechanisms that are hard to discover in a vertebrate are often readily revealed in the fly. This relates, as we now explain, to the frequency of gene duplication, which is substantially greater in vertebrate genomes than in the fly genome and has probably been crucial in making vertebrates the complex and subtle creatures that they are.
Okinawa Communicable Diseases Statement 2014
Introduction February 15, 2014
Asia and Japan now share the same boat economically, socially, and culturally at all level.
The outbreaks of SARS and novel avian influenza such as H7N9 have proved that the threats of communicable diseases to our health are ever increasing. At Kyushu Okinawa
Summit held in July 2000, Japan has launched “Okinawa Infectious Diseases Initiative”, calling out for global cooperation in taking actions against communicable diseases such as AIDS, tuberculosis, malaria, polio. Fourteen years since then, on February 14-15 th , 2014, on the same island of Okinawa, key persons in the very field from public and private sectors as well as governments and academia gathered to take part in “Nikkei Asian Conference”. The participants reached recognition that communicable diseases in Asia is and will always be one of the largest risks, and agreed to “Okinawa Communicable Diseases Statement 2014” as shown below.
I. Increasing Importance of Joint Efforts between Japan and Asian Countries in the Fight against Communicable Diseases
With more than half of population of the world,Asia including Japan is and will continue to be the center of the global economy and scientific community. As Japan and Asia become more and more interdependent, joint and coordinated efforts in this Region to fight against communicable diseases will be a pressing issue.
II. What is Expected of Japan
Given track record of Japan in the fight against communicable diseases as well as human,
technical and financial resources available in the country, the participants of the conference
expressed their wish that Japan would make further contributions to prevention and control of communicable diseases world wide. The same level of expectations was expressed
for Okinawa, given its unique geopolitical position and past experience in elimination of
such communicable diseases as filariasis and malaria.
III. Actions for Japan to Take in Order to Further
1) It is evident from our experience from global outbreaks including SARS that communicable diseases cause not only human health impact, but also serious impact on society and economy of a country. We also know well that once the pandemic settles down, society and mass media care less for the danger of communicable diseases and awareness towards crisis is not necessarily persistent. The society, corporate world as well as government need to take measures to strongly and continuously keep awareness towards communicable diseases.
2) Drawing upon Japan’s past experience and technical expertise available in the country, Japan should aim to develop and make available new medicines, vaccines, and diagnostic tools for health problems which are associated with high disease burden or are neglected, including zoonosis and multi-drug resistant tuberculosis. We have to develop innovative business models taking into account the experiences that we gained with initial efforts such as Global Health Innovative Technology Fund (GHIT).
3) Participants all agreed that the level of basic researches in Japan is high. However, on the part of researchers in Japan, the level of commitment to and interest in applying the fruits of the basic research to public health use is relatively low. While participants recognized some progress made, the system to fill the gap between basic research
and its application is still insufficient both in terms of human resources and financial investment. All stakeholders in Asia including private sectors are requested to make joint effort to address this gap.
4) Though clinical studies overseas and cooperation by other developing countries are
sometimes indispensable for development of new drugs such as those for multi-drug resistant bacteria such as MDR-TB and XDR-Acinetobacter, the system to implement the required collaboration has not yet been fully developed. Systems for collaboration between Japan and other countries in the area of clinical research have to be developed in such a way to benefit both parties. Toward that end, development and exchanges of human
resources in various level such as researchers and clinicians is necessary. If and when above is achieved, the time required for clinical trial will be extensively reduced.
5) Our regulatory system has not yet gained same level of recognition and respect as Western counterpart. We must reform further our regulatory authority in such a way that our regulatory system gains the international reputation in the area of safety, efficiency and ethics. It is important for Japan to strengthen collaboration with other countries, particularly neighboring countries.
6) Though there is a commonly held view that average life expectancy will not reach the level of industrialized countries unless GDP per capita exceeds a certain level, our experience has shown that that is not the case at all. As a matter of fact, our experiences have shown that life expectancy had already reached the level of the western industrialized countries even before the accelerated growth of GDP was made after the World War II. This illustrates the importance of public health measures, including effort to build equitable health systems and community participation and establishing public health centers. This message should be shared with other countries in Asia.
7) It is indispensable that Asia and Japan make closer collaboration and together address the challenges faced by communicable diseases. Towards that end, enhancing multi-layered network among all the stakeholders, the relevant organizations and countries as well as collaboration between private and public sectors are essential. While some progress has already been made in collaboration of all the relevant parties, further stride has to be made to translate the joint efforts into tangible outcomes in the spirit of “one health concept”.
8) Given Okinawa’s unique geopolitical and historical position and rich experience in the fight against communicable diseases, Okinawa is in the best position to serve as the center of Japan’s fight against communicable diseases in Asia and worldwide.
IV. Conclusive Words
The participants have agreed that this conference is the valuable first step to further enhance our fight against communicable diseases. Thus the participants strongly suggested that the organizer keep up this momentum by making further commitment to building upon the success of this first meeting and to continual dialogue and discussion among participants so that the further progress can be achieved.