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Understanding the Code of Life

What is a genome?

A genome is the full complement of genetic material encoded in the DNA+. of any living thing. A genome has been described as a “blueprint” for an organism’s structure and function. However, research is revealing that genomes are not static. Rather, they are dynamic and can be influenced by environmental factors and life experiences.

What is genomics?

Genomics is the science that aims to decipher and understand the entire genetic information of an organism (i.e. human, animal, plant or microorganism) encoded in its DNA and related molecules (i.e. RNA and proteins). Broadly speaking, Genome Canada’s definition of genomics includes related disciplines such as proteomics, metabolomics and bioinformatics.

What is genome sequencing?

The DNA sequence is a series of letters – As, Cs, Gs, and Ts – that represent the order of base pairs in a organism’s DNA. The sequence of a human genome is around three billion letters. As each person inherits one copy of their chromosomes (within which DNA is located) from their mother and another from their father, there are actually six billion letters to read and interpret.

DNA sequencing is a laboratory technique used to determine the sequence of units or bases (A, C, G, and T) in a DNA molecule.

In a sequencing laboratory, machines break the DNA up into manageable segments and read the order of the DNA bases or letters. Computers are then used to compare the DNA sequence with other sequences to locate the differences or variants.

Figure A Illustration of part of a strand of DNA (deoxyribonucleic acid), featuring labeled base pairs, adenine, cytosine, guanine and thymine. The sequence of bases makes up the unique genetic code of every individual organism.

Illustration of part of a strand of DNA (deoxyribonucleic acid), featuring labeled base pairs. The DNA molecule has a double helix arrangement, being composed of two right-handed spiral strands of sugar phosphates. These strands are held together by complementary pairs of four cross-linking nucleotide bases (colored rods): adenine, cytosine, guanine and thymine. The sequence of bases makes up the unique genetic code of every individual organism.

Figure B DNA nucleotide sequence

DNA nucleotide sequence

For more definitions, Genome British Columbia offers a comprehensive glossary of all things genomics.