Genes that control factors such as size, color and shape determine the differences in fruit. And now that scientists have discovered how to detect different genes, farmers can hand over a young and tender branch to have its genes checked prior to planting. It works the same way as a detective (侦探) checking finger-prints. Once farmers know which trees are good and which are bad, they can discard the bad ones. Farmers can even create new varieties according to their individual tastes.
In the past three years, tens of thousands of tests were carried out to determine the genetic (基因的) features of fruit. Zhang, a Chinese scientists, showed a photo of a DNA (脱氧核糖核酸)-test and pointed to the shining lines on it, saying that the lines were genetic signs that tell us what a tree’s fruit will be like. For example, the ordinary pear tree bears fruit after four years. But now it only takes a month to test the DNA from a young leaf and a farmer will know everything about its fruit. By mixing different types of trees with suitable genes, farmers can create whatever fruit trees they want.

The history of civil engineering is a very important story in the development of civilization. Civil engineers began practicing their profession four thousand years ago.
Consider the pyramids of Egypt. They are evidence that some of the earliest engineers had great scientific ability. They are also proof that those engineers could make lasting works of art and design. Although they lived thousands of years ago, the Egyptian engineers used very exact measurements. The base of the largest pyramid, the great pyramid near Gizeh, comes to within inches of being a perfect square. Each corner points toward the exact directions of north, south, east and west. The inside of the pyramid is filled with complicated passages and tunnels. These lead to different rooms inside the pyramid. Many of these passages are of great length and height.

Genes that control factors such as size, color and shape determine the differences in fruit. And now that scientists have discovered how to detect different genes, farmers can hand over a young and tender branch to have its genes checked prior to planting. It works the same way as a detective (侦探) checking finger-prints. Once farmers know which trees are good and which are bad, they can discard the bad ones. Farmers can even create new varieties according to their individual tastes.
In the past three years, tens of thousands of tests were carried out to determine the genetic (基因的) features of fruit. Zhang, a Chinese scientists, showed a photo of a DNA (脱氧核糖核酸)-test and pointed to the shining lines on it, saying that the lines were genetic signs that tell us what a tree’s fruit will be like. For example, the ordinary pear tree bears fruit after four years. But now it only takes a month to test the DNA from a young leaf and a farmer will know everything about its fruit. By mixing different types of trees with suitable genes, farmers can create whatever fruit trees they want.