DNA/Genes/Proteins – BBC commissioned 3 minute explanation

DNA is the instruction manual for how to build life. From microbes to plants to human beings, it defines us all. The complete set of instructions encoded in an organism’s DNA is called its “Genome”. This is passed from parent to offspring during reproduction. Information is stored in DNA using just four
types of molecule, which occur in pairs. There are billions of these pairs, organised in a
double-helix structure that is both strong and compact. These pairs also allow each strand to act as a backup for the other, a very efficient way to protect this precious genetic information. DNA folds into paired packages called chromosomes that are
stored in the nucleus of the cell. Different species have different numbers of chromosomes: humans have 23 pairs. Chromosomes contain many genes. A gene is a section of DNA that holds the instructions for a protein. Proteins are essential for life, and perform a huge variety of jobs, from controlling the function of a single cell, to
determining the shape of a whole organism. Within a species, each organism has very similar DNA. In human beings, the difference between one person and another is just 0.1%. But that is what makes us individuals, giving us
different facial features, hair colour and height. The uniqueness of our DNA can be used like a fingerprint, to identify us with an extraordinary degree of accuracy. By reading DNA, scientists have discovered that we share sequences not just with our own species, but also
with every other living thing on earth. Chimpanzees, one of our closest living relatives, share about 96% of our DNA. We also have genes in common with fish, plants and bacteria: powerful evidence that life came from a single ancestor millions of years ago. We haven’t just learned to read the instruction manual
for life, we can rewrite it as well. People have been manipulating DNA since before we knew it existed, selectively breeding plants and animals to bring out desired traits. Now, genetic engineering allows us to directly alter DNA
in a lab, creating new varieties of life. From plants that can resist disease or drought, to bacteria that can mass produce life saving hormones. But we don’t yet know what all of DNA does; lengthy sequences make no proteins at all, and have been (mistakenly?) labelled as junk. Some people are worried about these gaps in our knowledge, and unforeseen problems genetically modified foods may cause. What’s clear is that the instruction manual for life is more subtle, elegant and complex than we could have possibly imagined. DNA has revealed many of its secrets, but we still have much to learn.

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