A few days ago, Qingdao Customs intercepted a strange package.
This package is from the United States, and the declaration form when entering the country clearly fills in: clothes.
Oh, clothes? Customs officers inspected the package and found that there were only two pieces of clothing in the package, but 66 finger tubes were crowded. The openings of these finger tubes are sealed with plugs, and the inside is densely packed with eggs, larvae, pupae and adult worms of Drosophila nigricans. Roughly calculated, there are more than 7,000 of them.
These 7,000 black-bellied fruit flies are as difficult as ascending to the sky. So why are we so nervous about this living insect that doesn't dare to come in?
It's just bugs, what are people afraid of?
<h1 class="pgc-h-arrow-right" data-track="12" > the background of Drosophila nigris</h1>
Black-bellied fruit fly, as the name suggests "pro", it is really a "relative" of fruit flies, and many habits are similar to fruit flies.
For example, they are similar in size, with a body length of about 2.5 mm; the "hobbies" are the same, mostly inhabit rotten fruits, and their reproductive ability is amazing. The biggest difference is that the abdomen of the "black-bellied fruit fly" tends to be black or yellowish brown.
Humans have suffered great losses in fruit flies before.
At one time, the "Mediterranean fruit fly" in fruit flies was recognized as the "number one fruit killer" in the world. After three generations of breeding, a female Mediterranean fruit fly can make the number of flies in the area "over 100 million", and this process only takes about 60 days.
These flies feed on fruits such as citrus, apples, and pears, and even lay their eggs in fruits with high sugar content such as cherries, bayberry, and blueberries, which have a great impact on the harvest of fruit growers.
This time, the black-bellied fruit fly was originally a tropical or subtropical variety. Once they are inadvertently escaped into the natural environment, they become a scourge to local fruits. If they carry foreign germs or other biological-grade hidden dangers, they will lose more than just fruit.
<h1 class="pgc-h-arrow-right" data-track="58" > let's talk about gene editing</h1>
It's just bugs, isn't it a bit of a fuss to get to the "biological hazard"?
On this issue, it is not that some people are overly anxious. In fact, some scientists have already done so. Their means are through "gene editing."
Scientists know far more about drosophila than we thought.
As early as the beginning of the 20th century, scientists found that there are only 4 pairs of chromosomes in Drosophila melanogast, which is very suitable for the study of human genetics or disease mechanisms. American biologist Thomas Hunter Morgan proved that chromosomes are the carriers of genes through the hybridization experiment of fruit flies, and the disease proposed the "gene linkage-exchange law", one of the "three laws of genetics". In 1933, he was also awarded the Nobel Prize in Physiology or Medicine for his research in genetics.
In 2000, scientists sequenced the genes of Drosophila melanogasters. They found that the homology of the drosophila and the human genome sequence was as high as 60%, and that 75% of the known pathogenic genes in the human body were similar to those in the drosophila. That is to say, if you want to study the mechanism of human response to certain diseases, you can use this fruit fly to do it.
So far, scientists have used genetic induction in the laboratory to produce countless variants between these fruit flies.
For example, based on Mendel's laws of inheritance, scientists can artificially intervene in the genes that dominate the color of fruit flies' eyes so that they no longer produce red "pigments" normally, so that their eyes will appear white.
Eye color mutants Eye color mutants
Under this artificial intervention, the wing morphology of fruit flies also mutated. Scientists magnified defects on the second chromosome of Drosophila and found that these defective flies may have shorter wings than normal flies, and some with curly genes will also have curly wings.
Wing morphological mutant
Of course, similar mutations occur in fruit flies in body color and head morphology. This kind of artificial intervention of "mutation experiments" has been repeatedly successful, directly promoting the use of gene editing to give organisms a certain characteristic. For example, the "gene editing mosquito" that was frequently mentioned some time ago.
The mosquito is said to be able to interrupt the spread of malaria in its region through gene editing.
But when the scientists released the mosquitoes into nature, they found that everything was not as good as they thought, and even the offspring of these mosquitoes had "super mosquitoes" mixed with mutant genes. These "super mosquitoes" are more contagious, and it is difficult for ordinary pesticides to eliminate them.
Returning to the more than 7,000 black-bellied fruit flies intercepted by customs this time, are there any gene-editing characteristics on them? Do you carry some germs that affect people? Whatever the intent of the intercepted American parcel, it is not too strict to beware of biological attacks.
The documentary "I Am a Scientific Man" is specially sponsored by Changan Trust.