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The formal main gate of the Forbidden City, which a person can walk through only once in a lifetime, and only in one direction - in but never out
When it comes to the gates of the Forbidden City, few people can say clearly just how many gates the whole palace complex has, but there is one gate that everyone is certainly familiar with. It is the Meridian Gate (Wumen), the one that anyone visiting the Forbidden City must pass through, the formal main gate of the Forbidden City....
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Marker-assisted selection will become the main direction of future breeding
Conventional breeding methods have limitations such as genetic variation and genome hybridization; in principle, these limitations can be overcome through genetic engineering methods (such as recombinant DNA). Using these methods, genes with defined functions can be cloned and introduced into different species in a rapid and highly specialized manner.