The public genome data have been polluted

The public genome data have been polluted
To in the public genome database that the global scientist is open, nearly have 1/5 of the bacteria, plant and it is not that the genome data of the primate receive the pollution of the human gene! This thesis that U.S.A. Connecticut university publishes newly causes the extensive concern, magazines such as " Nature ", " scientist ",etc. have made reports on its official site as soon as possible.

As the basic data source of scientific research of the life, every big bus genome database is downloaded, quoted by hundreds and thousands of laboratories in the world every day, engaged in follow-up study. However, these passwords used for understanding the life secret have been polluted - -How to cause? And how to reply? There are anxious on a lot of people,initial data on whose name is wrong how much curiosity and how much hardships be led to a blind alley to be paid.

The pollution risk is hidden in each order-checking link

"The genome data are polluted, will probably begin when the sample is dealt with. " Shanghai biochemistry and cell researcher of research institute Guo Li of Chinese Academy of Sciences and telling reporters, in order to obtain the order-checking sample of enough quantity, will amplify the species gene examined of small quantity very much at first in every laboratory, one of the methods is to utilize bacteria such as Escherichia coli,etc. to amplify, train the genetic sample. Though train the requirement to go on in the clean environment, if misoperation, it is possible as the bacterium of culture medium " While the crack " Mix with the sample.

Another kind is known as " PCR " That if you can't last technology acid totally, last manual working,pollution more in source: Probably the bacterium in the air has fallen in the sample, may still remain the genetic fragment in reagent after sterilizing too, but the most common pollution sources may be scientist, for example before amplifying, a cell of the experimenter's has floated into sample.

Although can not see the naked eye, people are spreading one's own DNA, a purity of the sample that breath may destroy and check order, touching all the time. Molecule geneticists of U.S.A. Connecticut university Rachel and O'Neal say in the thesis: He and laboratory colleague repeat the array Alu component with the human specificity, not sifted and checked, to 2749 in four public genome databases in the world found by primates' primitive array genome, there are 492 pollution with human Alu component array - -The polluting the proportion of 18% " It has been already high as to must be paid attention to " .

In fact, any link that pollution may be checking order takes place. So, it is not merely to one's own protection that researchers wear gloves, gauze mask and test, can also prevent the sample from receiving one's own pollution. Very such simple operational procedure has not been placed on in the heart by a lot of experiment personnel. Guo Li and showing, looks on as gene sequencing and becomes the routine in scientific research of the life, the operation of many researchers makes at will too, it is just the pollution sources hidden in the minds of people not to bother about small matters.

The persons who send cut corrupt first " The filter screen "

All-pervasive bacterium, the spray of saliva suspended in the air, these other source genes impossible to defend seem to imply, it is impossible for gene sequencing to accomplish a pollution. Then, is there measure remedied afterwards? The national human genome southern research center researcher Han ZeGuang points out, the data that a great part is polluted can actually be filtered. "In to send data by public the intersection of genome and database, we will check order result and huge database make than right in the computer. " He says, it just like uses the software scanning to filter the course of pollution, and the persons who send are most clear the other source gene probably meddled in the whole course, therefore the choice is appropriate " The software " .

Strict experimental design can " Intercept " Pollute partly. Guo Li and saying, DNA is made up of two strands, the rigorous scientist will check order to two chains respectively and then prove each other.

If first dish filter pass firm, have second and third " filter screen " subsequently then . Database administrator does not hesitate to face and present the magnanimity data that geometric progression increases the public genome, it is filtered and corrected the initial data from countries all over the world but there is responsibility all the time, pollute in conformity with the mark at least, in order to remind the data users take care in " trap " .

Finally, when the global scientist shares and utilizes the public genome data to do follow-up study, a heart is essential that many. Otherwise, are probably led by the nose by the wrong data, consume a large amount of energy in vain, even draw the wrong scientific conclusion.

Han ZeGuang says, once a large number of theses reported the genetic level shifted the phenomenon among the species before this, can't help letting people suspect that there is a part that result from the reason that the data are polluted nowadays.

The most serious misleading may take place in the fields of new medicine development and clinical research. "You know, it is very simple to find Alu component in a fish's sample, but the sample looking for another person in a human sample will be very difficult. If decide the individualized healing solution according to the array polluted, may cause the tragedy different to imagine. " O'Neal says.

Draw lessons from ancient DNA and study the norm, OK

"Genetic pollution is a big problem, but not a new problem. This thesis may remind the researcher to be engaged in gene studies with more prudent attitude. " This lets many scholars engaged in ancient DNA research remember a section of past event: In 1994, someone claimed to get the ancient DNA array from dinosaur's skeleton chip, found later that was actually a human bit of DNA - -Those extinct plants and animal fossil have been polluted by the scientist own DNA. Hereafter, the norm progressively of technology of abstraction and checking order of ancient DNA.

Modern anthropology key Li Hui, associate professor of laboratory of Ministry of Education of Fudan University tells reporters, from sampling beginning, ancient DNA follows a set of tight and severe procedure when being studied - -In the scene of exploration, once find samples such as the skeleton,etc., researchers must wear the glove, gauze mask and cap at once, put sample into aseptic sample bag, take back the laboratory to seal and keep subsequently.

Following DNA draw and check order, want, go on in ten thousand aseptic laboratory purified to exceed. From sample being thick to wash to get into the cave, sample, collect, mix reagent,etc. to DNA and then, every step want, make in independent room totally, finish a sample each time, all need to sterilize air filtration and ultraviolet ray. In the whole course, the researcher must be " in full battle gear " ,Even eyes can't be exposed - -Wear the transparent eye-shade.

Even so, will pollute or have, but can limit to 1% at least. Li Hui says, in order to guarantee the data are accurate, each experiment will be repeated for three times, staff members have all examined DNA in advance, in order to discern possible pollution.

It is easy to imagine, ancient DNA studies " it is corrupt to defend " The tactics are taking high cost as cost, and so high cost, large-scale gene sequencing is nearly unable to bear. For this reason, more people throw sight to learn home from biological information, hope they can improve present genome data pollution and filter the system, it will be good to " manage pollution " Check on people. Staff reporter Ren Quan


The public genome data have been polluted