Related topics: genome · genes · protein · genetic variation · dna

How to turn specific genes on and off

All the cells in an individual's body bear the same genetic code. It is the reading and writing of this code—the "turning on" and "turning off" of specific genes in specific cells—that gives the cells their identities. ...

Our DNA is becoming the world's tiniest hard drive

Our genetic code is millions of times more efficient at storing data than existing solutions, which are costly and use immense amounts of energy and space. In fact, we could get rid of hard drives and store all the digital ...

Expanding the genetic code with quadruplet codons

One of modern biologists' most ambitious goals is to learn how to expand or otherwise modify the genetic code of life on Earth, in order to make new, artificial life forms. Part of the motivation for this "synthetic biology" ...

Herbicide resistance no longer a black box for scientists

When agricultural weeds evolve resistance to herbicides, they do it in one of two ways. In target-site resistance, a tiny mutation in the plant's genetic code means the chemical no longer fits in the protein it's designed ...

Calling through the 'DNA wire'

Proteins can communicate through DNA, conducting a long-distance dialog that serves as a kind of genetic "switch," according to Weizmann Institute of Science researchers. They found that the binding of proteins to one site ...

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Genetic code

The genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences) by living cells. The code defines a mapping between tri-nucleotide sequences, called codons, and amino acids. A triplet codon in a nucleic acid sequence usually specifies a single amino acid (though in some cases the same codon triplet in different locations can code unambiguously for two different amino acids, the correct choice at each location being determined by context). Because the vast majority of genes are encoded with exactly the same code (see the RNA codon table), this particular code is often referred to as the canonical or standard genetic code, or simply the genetic code, though in fact there are many variant codes. Thus the canonical genetic code is not universal. For example, in humans, protein synthesis in mitochondria relies on a genetic code that varies from the canonical code.

It is important to know that not all genetic information is stored using the genetic code. All organisms' DNA contain regulatory sequences, intergenic segments, and chromosomal structural areas that can contribute greatly to phenotype but operate using distinct sets of rules that may or may not be as straightforward as the codon-to-amino acid paradigm that usually underlies the genetic code (see epigenetics).

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